microblaze: Save and restore msr in hw exception

I thought that this part of code could be removed because just
save and restore MSR but any code can't change it. But seems to
that any part of code works with this information.

This patch solved problem with allocation.

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

arch/microblaze/kernel/hw_exception_handler.S

@@ -84,9 +84,10 @@
 #define NUM_TO_REG(num)		r ## num
 
 #ifdef CONFIG_MMU
-/* FIXME you can't change first load of MSR because there is
- * hardcoded jump bri 4 */
 	#define RESTORE_STATE			\
+		lwi	r5, r1, 0;		\
+		mts	rmsr, r5;		\
+		nop;				\
 		lwi	r3, r1, PT_R3;		\
 		lwi	r4, r1, PT_R4;		\
 		lwi	r5, r1, PT_R5;		\
@@ -309,6 +310,9 @@ _hw_exception_handler:
 	lwi	r31, r0, TOPHYS(PER_CPU(CURRENT_SAVE)) /* get saved current */
 #endif
 
+	mfs	r5, rmsr;
+	nop
+	swi	r5, r1, 0;
 	mfs	r3, resr
 	nop
 	mfs	r4, rear;