build: break compiler flags out of $(CC)

Having more than the executable in $(CC) only leads to
trouble in a number of situations.

Change-Id: I7642ca4068b3a3bd5798219d74de9e0eb85bb4e5
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/5769
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/arch/x86/Makefile.inc

@@ -28,7 +28,7 @@ subdirs-y += lib
 subdirs-y += smp
 
 ifeq ($(CONFIG_COMPILER_GCC),y)
-DISASSEMBLY=-Wa,-acdlns
+DISASSEMBLY=-Wa,-acdlns $(CFLAGS_x86_32)
 else
 DISASSEMBLY=
 endif