xfs: Remove boolean_t typedef completely.

Since we are using C99 we have one builtin defined in include/linux/types.h,
use that instead.

v2: you missed one in fs/xfs/xfs_qm_bhv.c, cleaned up. -bpm

Signed-off-by: Thiago Farina <tfarina@chromium.org>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>