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>

1 files changed, 3 insertions, 0 deletions

diff --git a/README b/README
index f371e0e299..33bda8c929 100644
--- a/README
+++ b/README
@@ -3898,6 +3898,9 @@ Low Level (hardware related) configuration options:
 		a second time.	Useful for platforms that are pre-booted
 		by coreboot or similar.
 
+- CONFIG_PCI_INDIRECT_BRIDGE:
+		Enable support for indirect PCI bridges.
+
 - CONFIG_SYS_SRIO:
 		Chip has SRIO or not