powerpc: Setup BHRB instructions facility in HFSCR for POWER8

Make BHRB instructions available in problem and privileged states.

Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 5c6fbe2..178a858 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -272,6 +272,7 @@
 #define   HFSCR_TAR	(1 << (63-55)) /* Enable Target Address Register */
 #define   HFSCR_TM	(1 << (63-58)) /* Enable Transactional Memory */
 #define   HFSCR_PM	(1 << (63-60)) /* Enable prob/priv access to PMU SPRs */
+#define   HFSCR_BHRB	(1 << (63-59)) /* Enable Branch History Rolling Buffer*/
 #define   HFSCR_DSCR	(1 << (63-61)) /* Enable Data Stream Control Register */
 #define   HFSCR_VECVSX	(1 << (63-62)) /* Enable VMX/VSX  */
 #define   HFSCR_FP	(1 << (63-63)) /* Enable Floating Point */