ppc4xx: Remove duplicated is_pci_host() functions

This patch introduces a weak default function for is_pci_host(),
returning 1. This is the default behaviour, since most boards only
implement PCI host functionality. This weak default can be overridden
by a board specific version if needed.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/esd/du440/du440.c b/board/esd/du440/du440.c
index d0e52cb..8f9f950 100644
--- a/board/esd/du440/du440.c
+++ b/board/esd/du440/du440.c
@@ -498,27 +498,6 @@
 }
 #endif /* defined(CONFIG_PCI) && defined(CONFIG_SYS_PCI_MASTER_INIT) */
 
-/*
- * is_pci_host
- *
- * This routine is called to determine if a pci scan should be
- * performed. With various hardware environments (especially cPCI and
- * PPMC) it's insufficient to depend on the state of the arbiter enable
- * bit in the strap register, or generic host/adapter assumptions.
- *
- * Rather than hard-code a bad assumption in the general 440 code, the
- * 440 pci code requires the board to decide at runtime.
- *
- * Return 0 for adapter mode, non-zero for host (monarch) mode.
- */
-#if defined(CONFIG_PCI)
-int is_pci_host(struct pci_controller *hose)
-{
-	/* always configured as host. */
-	return (1);
-}
-#endif /* defined(CONFIG_PCI) */
-
 int last_stage_init(void)
 {
 	int e, i;
diff --git a/board/esd/pmc440/pmc440.c b/board/esd/pmc440/pmc440.c
index ec92552..10901b4 100644
--- a/board/esd/pmc440/pmc440.c
+++ b/board/esd/pmc440/pmc440.c
@@ -712,7 +712,7 @@
 }
 
 /*
- * is_pci_host
+ * Override weak is_pci_host()
  *
  * This routine is called to determine if a pci scan should be
  * performed. With various hardware environments (especially cPCI and