microblaze: Typo s/use use/use/

Trivial patch.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/include/asm/pgtable.h

@@ -200,7 +200,7 @@ static inline pte_t pte_mkspecial(pte_t pte)	{ return pte; }
  * is cleared in the TLB miss handler before the TLB entry is loaded.
  * - All other bits of the PTE are loaded into TLBLO without
  *  * modification, leaving us only the bits 20, 21, 24, 25, 26, 30 for
- * software PTE bits.  We actually use use bits 21, 24, 25, and
+ * software PTE bits.  We actually use bits 21, 24, 25, and
  * 30 respectively for the software bits: ACCESSED, DIRTY, RW, and
  * PRESENT.
  */