aice: fix FTBFS on ARM

aice: fix FTBFS on ARM

This fixes a bunch of errors like this:
aice_usb.c: In function 'aice_pack_htdc':
aice_usb.c:63:4: error: cast increases required alignment of target type [-Werror=cast-align]

Compile-tested only.

I think this can be seen as another justification for an ARM Jenkins
build target.

Also, the aice code I've seen so far seems to be assuming it runs on a
little-endian machine so probably there're some endianness issues
hiding. Hsiangkai, please get an old PowerPC Mac (or at least some
fast usb-equipped MIPS SOHO WiFi AP/router for which you can
cross-compile OpenOCD with OpenWrt) and do some real-life testing for
your code on Big-Endian. I propose it to be a requirement for any
non-trivial code submitted by a commercial entity of reasonable size.

Change-Id: I45e05257687d0020d7172b26a8666ebc1950e00c
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1477
Tested-by: jenkins
Reviewed-by: Hsiangkai Wang <hsiangkai@gmail.com>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>