ppc/85xx: Map boot page guarded for MP boot

We already map the page cache-inhibited.  There is no reason we
shouldn't also be marking it guarded to prevent speculative accesses.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/board/freescale/p2020ds/tlb.c b/board/freescale/p2020ds/tlb.c
index b2e562a..36ad086 100644
--- a/board/freescale/p2020ds/tlb.c
+++ b/board/freescale/p2020ds/tlb.c
@@ -47,7 +47,7 @@
 	/* TLB 1 */
 	/* *I*** - Covers boot page */
 	SET_TLB_ENTRY(1, 0xfffff000, 0xfffff000,
-		      MAS3_SX|MAS3_SW|MAS3_SR, MAS2_I,
+		      MAS3_SX|MAS3_SW|MAS3_SR, MAS2_I|MAS2_G,
 		      0, 0, BOOKE_PAGESZ_4K, 1),
 
 	/* *I*G* - CCSRBAR */