microblaze: Consolidate cache code

Merge cpu and lib cache code.
Flush cache before disabling.

Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/lib/Makefile

@@ -29,7 +29,6 @@ SOBJS-y	+=
 
 COBJS-y	+= board.o
 COBJS-y	+= bootm.o
-COBJS-y	+= cache.o
 COBJS-y	+= time.o
 
 SRCS	:= $(SOBJS-y:.o=.S) $(COBJS-y:.o=.c)