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>

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 */

arch/powerpc/kernel/cpu_setup_power.S

@@ -129,7 +129,8 @@ __init_FSCR:
 
 __init_HFSCR:
 	mfspr	r3,SPRN_HFSCR
-	ori	r3,r3,HFSCR_TAR|HFSCR_TM|HFSCR_DSCR|HFSCR_VECVSX|HFSCR_FP|HFSCR_PM
+	ori	r3,r3,HFSCR_TAR|HFSCR_TM|HFSCR_BHRB|HFSCR_PM|\
+				HFSCR_DSCR|HFSCR_VECVSX|HFSCR_FP
 	mtspr	SPRN_HFSCR,r3
 	blr