powerpc: Clear the BSS at the start of early_init with ARCH=ppc

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index e68f848..b95f7cf 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -294,6 +294,10 @@
 {
 	unsigned long offset = reloc_offset();
 
+	/* First zero the BSS -- use memset_io, some platforms don't have
+	 * caches on yet */
+	memset_io(PTRRELOC(&__bss_start), 0, _end - __bss_start);
+
 	/*
 	 * Identify the CPU type and fix up code sections
 	 * that depend on which cpu we have.