media: fimc-capture: get rid of two warnings

Smatch produces two warnings when building this file:
	./arch/x86/include/asm/bitops.h:433:22: warning: asm output is not an lvalue
	./arch/x86/include/asm/bitops.h:433:22: warning: asm output is not an lvalue

On some asm instructions.

I suspect that those asm instructions might not be producing the
right code, so, better to use two intermediate vars, get rid of
the warnings and of the risk of producing a wrong code.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>