Makefile: fix up CROSS_COMPILE and READABLE_ASM interaction.

When the READABLE_ASM cc-option tests were added they were done so prior
to the arch Makefile include, resulting in cc-option being run on the
host cc instead of the factoring in the cross prefix set up by the
architecture.

This bumps the include back up so that cc-option actually runs on the
compiler that we're building with.

Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>