MIPS: Netlogic: Add support for XLP2XX

XLP2XX is first in the series of 28nm XLPII processors.

The changes are to:
* Add processor ID for XLP2XX to asm/cpu.h and kernel/cpu-probe.c.
* Add a cpu_is_xlpii() function to check for XLPII processors.
* Update xlp_mmu_init() to use config4 to enable extended TLB.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5698/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index c198615..71b9f19 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -179,6 +179,7 @@
 
 #define PRID_IMP_NETLOGIC_XLP8XX	0x1000
 #define PRID_IMP_NETLOGIC_XLP3XX	0x1100
+#define PRID_IMP_NETLOGIC_XLP2XX	0x1200
 
 /*
  * Definitions for 7:0 on legacy processors