Disintegrate asm/system.h for Microblaze

Disintegrate asm/system.h for Microblaze.  Not compiled.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: microblaze-uclinux@itee.uq.edu.au

arch/microblaze/kernel/cpu/pvr.c

@@ -12,7 +12,6 @@
 
 #include <linux/kernel.h>
 #include <linux/compiler.h>
-#include <asm/system.h>
 #include <asm/exceptions.h>
 #include <asm/pvr.h>