microblaze: Define correct L1_CACHE_SHIFT value

Microblaze cacheline length is configurable and current cpu
uses two cacheline length 4 and 8.

We are taking conservative maximum value to be sure that cacheline
alignment is satisfied for all cases.

Here is the calculation for cacheline lenght 8  32bit=4Byte values
which is corresponding with SHIFT 5.
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/cache.h

@@ -15,7 +15,7 @@
 
 #include <asm/registers.h>
 
-#define L1_CACHE_SHIFT	2
+#define L1_CACHE_SHIFT 5
 /* word-granular cache in microblaze */
 #define L1_CACHE_BYTES	(1 << L1_CACHE_SHIFT)