Introduce ARCv2 architecture related code

Introduce ARCv2 architecture related code

This patch is an initial bump of ARC-specific code
which implements the ARCv2 target(EMSK board) initializing
routine and some basic remote connection/load/continue
functionality.

Changes:
03.12.2019:
-Add return value checks.
-Using static code analizer next fixes were made:
        Mem leak in functions:
                arc_jtag_read_memory,arc_jtag_read_memory,
                arc_jtag_write_registers, arc_jtag_read_registers,
                jim_arc_add_reg_type_flags, jim_arc_add_reg_type_struct,
                arc_build_reg_cache, arc_mem_read.
        Dead code in "arc_mem_read";
        In arc_save_context, arc_restore_context correct arguments
        in"memset" calls.
        In "build_bcr_reg_cache", "arc_build_reg_cache" check
        if list is not empty.

29.12.2019
-Moved code from arc_v2.c to arc.c
-Added checks of the result of calloc/malloc calls
-Reworked arc_cmd.c: replaced spagetty code with functions
-Moved to one style in if statements - to "if(!bla)"
-Changed Licence headers

22.01.2020
-Removed unused variables in arc_common
-Renamed register operation functions
-Introduced arc_deinit_target function
-Fixed interrupt handling in halt/resume:
        * add irq_state field in arc_common
        * fix irq enable/disable calls ( now STATUS32 register is used)
-Switched from buf_set(get)_us32() usage to target_buffer_set(get)_u32()
-Made some cleanup

30.01.2020
-Removed redundant arc_register struct, moved target link to arc_reg_desc
-Introduced link to BCR reg cache in arc_common for freeing memory.
-Now arc_deinit_target frees all arc-related allocated memory.
	Valgrind shows no memory leaks.
-Inroduced arch description in arc.c

01.02.2020
-Remove small memory allocations in arc_init_reg. Instead created reg_value
	and feature fields in arc_reg_desc.
-Add return value for arc_init_reg() func.
-Replaced some integer constants(61,62,63) with defines.
-Removed redundant conversions in arc_reg_get_field().
-Moved iccm/dccm configuration code from arc_configure()
	to separate functions.

19.02.2020
-Change sizeof(struct) to sizeof(*ptr) in allocations
-Changed if/while(ptr != NULL) to if/while(ptr)
-Removed unused variables from struct arc_jtag
-Add additional structs to arc_reg_data_type
 to reduce amount of memory allocations calls
 and simplifying memory freeing.
-Add helper arc_reg_bitfield_t struct which includes
 reg_data_type_bitfield object and char[] name. Reduces
 memory allocations calls.
-Add limit for reg_type/reg_type_field names(20 symbols).
-Add in jim_arc_add_reg_type*() functions additional
 argnument checks(amount of field/name size).
-In jim_arc_add_reg_type*() reduced amount of memory allocations.
-Cleanup of jim_arc_add_reg_type*() functions.
-For commands update ".usage" fields according docopt.
-Cleanup in arc_jtag.c
-Renamed functions which require jtag_exeutre_queue() to arc_jtag_enque_*()
-Add arc_jtag_enque_register_rw() function, which r/w to jtag ir/dr regs
 during regiter r/w.

24.02:
-Change include guards in arc* files according coding style
-Remove _t suffix in struct arc_reg_bitfield_t
-Some cleanup

Change-Id: I6ab0e82b12e6ddb683c9d13dfb7dd6f49a30cb9f
Signed-off-by: Evgeniy Didin <didin@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Reviewed-on: http://openocd.zylin.com/5332
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>