ppc: Move reset_status to arch_global_data

Move this field into arch_global_data and tidy up.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc512x/cpu_init.c b/arch/powerpc/cpu/mpc512x/cpu_init.c
index fe6beaf..32ade1b 100644
--- a/arch/powerpc/cpu/mpc512x/cpu_init.c
+++ b/arch/powerpc/cpu/mpc512x/cpu_init.c
@@ -62,7 +62,7 @@
 #endif
 
 	/* RSR - Reset Status Register - clear all status */
-	gd->reset_status = im->reset.rsr;
+	gd->arch.reset_status = im->reset.rsr;
 	out_be32(&im->reset.rsr, ~RSR_RES);
 
 	/*