common: Move pci_init_board() out of common.h

This function can be dropped when all boards use driver model for PCI. For
now, move it into init.h with a comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/board/sbc8641d/sbc8641d.c b/board/sbc8641d/sbc8641d.c
index fb5db6c..0a9dab8 100644
--- a/board/sbc8641d/sbc8641d.c
+++ b/board/sbc8641d/sbc8641d.c
@@ -13,6 +13,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <init.h>
 #include <pci.h>
 #include <asm/processor.h>
 #include <asm/immap_86xx.h>