85xx: Add basic e500mc core support

Introduce CONFIG_E500MC to deal with the minor differences between
e500v2 and e500mc.

* Certain fields of HID0/1 don't exist anymore on e500mc
* Cache line size is 64-bytes on e500mc
* reset value of PIR is different

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/cpu/mpc85xx/cpu.c b/cpu/mpc85xx/cpu.c
index b8f9125..c780687 100644
--- a/cpu/mpc85xx/cpu.c
+++ b/cpu/mpc85xx/cpu.c
@@ -134,6 +134,10 @@
 	    puts("Unknown");
 	    break;
 	}
+
+	if (PVR_MEM(pvr) == 0x03)
+		puts("MC");
+
 	printf(", Version: %d.%d, (0x%08x)\n", major, minor, pvr);
 
 	get_sys_info(&sysinfo);