microblaze: trivial: Fix typo fault

descrtiption -> description

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

arch/microblaze/include/asm/pvr.h

@@ -111,7 +111,7 @@ struct pvr_s {
 /* Target family PVR mask */
 #define PVR10_TARGET_FAMILY_MASK	0xFF000000
 
-/* MMU descrtiption */
+/* MMU description */
 #define PVR11_USE_MMU			0xC0000000
 #define PVR11_MMU_ITLB_SIZE		0x38000000
 #define PVR11_MMU_DTLB_SIZE		0x07000000