Workaround for a gcc-4.6 bug on -fstrict-volatile-bitfields.

http://gcc.gnu.org/ml/gcc-patches/2011-03/msg01477.html
http://gcc.gnu.org/ml/gcc-patches/2011-11/msg01390.html

-fstrict-volatile-bitfields is set on by default on gcc-4.6
for ARM target. This causes an inline asm() error. While
upstream gcc community is working on the patch, we shut
off this option temporarily.

This patch does not affect gcc-4.4.3 build.

Change-Id: Id7016dc5856a516e10f2617232945034728a74ab