microblaze: Add missing irqflags.h header

Without this header local_save_flags() is not defined.
Signed-off-by: Stefan Asserhall <stefan.asserhall@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

arch/microblaze/kernel/cpu/pvr.c

@@ -14,6 +14,7 @@
 #include <linux/compiler.h>
 #include <asm/exceptions.h>
 #include <asm/pvr.h>
+#include <linux/irqflags.h>
 
 /*
  * Until we get an assembler that knows about the pvr registers,