microblaze: Define tlb_flush macro

This fix remove bug which we had till now in all
Microblaze MMU code. Primary tested on mmap01 LTP test.
We forget to flush invalid tlb which were changed - we
used them and there were wrong old data which wasn't correct.
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/tlb.h

@@ -11,7 +11,7 @@
 #ifndef _ASM_MICROBLAZE_TLB_H
 #define _ASM_MICROBLAZE_TLB_H
 
-#define tlb_flush(tlb)	do {} while (0)
+#define tlb_flush(tlb)	flush_tlb_mm((tlb)->mm)
 
 #include <asm-generic/tlb.h>