microblaze: Fix a typo when disabling stack protection

Correct a typo causing the stack protector to be left enabled.
0xFFFFFFF -> 0xFFFFFFFF

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/kernel/head.S

@@ -66,7 +66,7 @@ real_start:
 	mts	rmsr, r0
 /* Disable stack protection from bootloader */
 	mts	rslr, r0
-	addi	r8, r0, 0xFFFFFFF
+	addi	r8, r0, 0xFFFFFFFF
 	mts	rshr, r8
 /*
  * According to Xilinx, msrclr instruction behaves like 'mfs rX,rpc'