powerpc/85xx: Cleanup how SVR_MAJ() is defined on MPC8536

The MPC8536 seems to use only 3 bits for the major revision field in the
SVR rather than the 4 bits used by all other processors.  The most
significant bit is used as a mfg code on MPC8536.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 50af6e7..46f9989 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -1022,7 +1022,11 @@
 #define SVR_FAM(svr)	(((svr) >> 20) & 0xFFF)	/* Family field */
 #define SVR_MEM(svr)	(((svr) >> 16) & 0xF)	/* Member field */
 
+#ifdef CONFIG_MPC8536
+#define SVR_MAJ(svr)	(((svr) >>  4) & 0x7)	/* Major revision field*/
+#else
 #define SVR_MAJ(svr)	(((svr) >>  4) & 0xF)	/* Major revision field*/
+#endif
 #define SVR_MIN(svr)	(((svr) >>  0) & 0xF)	/* Minor revision field*/
 
 /* Some parts define SVR[0:23] as the SOC version */