powerpc: Correct FSCR bit definitions

Commit 74e400ce ("powerpc: Rework setting up H/FSCR bit definitions")
ended up with incorrect bit numbers for FSCR_PM_LG and FSCR_BHRB_LG.
This fixes them.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/reg.h

@@ -258,8 +258,8 @@
 #define FSCR_TAR_LG	8	/* Enable Target Address Register */
 #define FSCR_EBB_LG	7	/* Enable Event Based Branching */
 #define FSCR_TM_LG	5	/* Enable Transactional Memory */
-#define FSCR_PM_LG	4	/* Enable prob/priv access to PMU SPRs */
-#define FSCR_BHRB_LG	3	/* Enable Branch History Rolling Buffer*/
+#define FSCR_BHRB_LG	4	/* Enable Branch History Rolling Buffer*/
+#define FSCR_PM_LG	3	/* Enable prob/priv access to PMU SPRs */
 #define FSCR_DSCR_LG	2	/* Enable Data Stream Control Register */
 #define FSCR_VECVSX_LG	1	/* Enable VMX/VSX  */
 #define FSCR_FP_LG	0	/* Enable Floating Point */