microblaze: Disable all cpu features before reset

Fix microblaze soft reset function and disable
all cpu features. Especially disable caches because
IRQs were off by disable_interrupts().

Reported-by: John Williams <john.williams@xilinx.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

board/xilinx/microblaze-generic/microblaze-generic.c

@@ -40,7 +40,8 @@ int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 #endif
 
 	puts ("Reseting board\n");
-	asm ("bra r0");
+	__asm__ __volatile__ ("	mts rmsr, r0;" \
+				"bra r0");
 
 	return 0;
 }