skia: update armv6 support

* Remove some hacks
* Add thumb1 support for assembly code
* Add a workaround for a GCC bug

Change-Id: I3d07dccce58227588552699c02e259dd13e0601c
Signed-off-by: Marco Milanese <marcomilanese7@gmail.com>
Conflicts:
	Android.mk
	bench/Android.mk
	include/core/SkFixed.h
	src/core/SkOnce.h
	src/opts/SkBitmapProcState_opts_arm.cpp
	tests/Android.mk