pci: introduce CONFIG_PCI_INDIRECT_BRIDGE option

The pci_indirect.c file is always compiled when
CONFIG_PCI is defined although the indirect PCI
bridge support is not needed by every board.

Introduce a new CONFIG_PCI_INDIRECT_BRIDGE
config option and only compile indirect PCI
bridge support if this options is enabled.

Also add the new option into the configuration
files of the boards which needs that.

Compile tested for powerpc, x86, arm and nds32.
MAKEALL results:

powerpc:
  --------------------- SUMMARY ----------------------------
  Boards compiled: 641
  Boards with warnings but no errors: 2 ( ELPPC MPC8323ERDB )
  ----------------------------------------------------------
  Note: the warnings for ELPPC and MPC8323ERDB are present even
  without the actual patch.

x86:
  --------------------- SUMMARY ----------------------------
  Boards compiled: 1
  ----------------------------------------------------------

arm:
  --------------------- SUMMARY ----------------------------
  Boards compiled: 311
  ----------------------------------------------------------

nds32:
  --------------------- SUMMARY ----------------------------
  Boards compiled: 3
  ----------------------------------------------------------

Cc: Tom Rini <trini@ti.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
diff --git a/include/configs/xpedite520x.h b/include/configs/xpedite520x.h
index ff99481..3034a3c 100644
--- a/include/configs/xpedite520x.h
+++ b/include/configs/xpedite520x.h
@@ -48,6 +48,7 @@
 #define CONFIG_PCI_SCAN_SHOW	1	/* show pci devices on startup */
 #define CONFIG_PCI1		1	/* PCI controller 1 */
 #define CONFIG_FSL_PCI_INIT	1	/* Use common FSL init code */
+#define CONFIG_PCI_INDIRECT_BRIDGE 1	/* indirect PCI bridge support */
 #define CONFIG_SYS_PCI_64BIT	1	/* enable 64-bit PCI resources */
 #define CONFIG_FSL_LAW		1	/* Use common FSL init code */