powerpc/8xxx: Add is_core_disabled to remove disabled cores from dtb

If we explicitly disabled a core remove it from the dtb we pass on to
the kernel.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/cpu/mpc85xx/mp.c b/arch/powerpc/cpu/mpc85xx/mp.c
index ddbc221..e05257c 100644
--- a/arch/powerpc/cpu/mpc85xx/mp.c
+++ b/arch/powerpc/cpu/mpc85xx/mp.c
@@ -77,6 +77,13 @@
 
 	return 0;
 }
+
+int is_core_disabled(int nr) {
+	ccsr_gur_t *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+	u32 coredisrl = in_be32(&gur->coredisrl);
+
+	return (coredisrl & (1 << nr));
+}
 #else
 int cpu_disable(int nr)
 {
@@ -96,6 +103,22 @@
 
 	return 0;
 }
+
+int is_core_disabled(int nr) {
+	ccsr_gur_t *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+	u32 devdisr = in_be32(&gur->devdisr);
+
+	switch (nr) {
+	case 0:
+		return (devdisr & MPC85xx_DEVDISR_CPU0);
+	case 1:
+		return (devdisr & MPC85xx_DEVDISR_CPU1);
+	default:
+		printf("Invalid cpu number for disable %d\n", nr);
+	}
+
+	return 0;
+}
 #endif
 
 static u8 boot_entry_map[4] = {