mx6sxsabresd: Add PCI support

Tested with an Intel Wireless PCI 7260HMW card:

U-Boot 2014.10-rc1-16576-g4a8a8a8-dirty (Aug 23 2014 - 16:05:11)

CPU:   Freescale i.MX6SX rev1.0 at 792 MHz
Reset cause: WDOG
Board: MX6SX SABRE SDB
I2C:   ready
DRAM:  1 GiB
MMC:   FSL_SDHC: 0
  00:01.0     - 16c3:abcd - Bridge device
   01:00.0    - 8086:08b1 - Network controller

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

include/configs/mx6sxsabresd.h

@@ -198,6 +198,16 @@
 #define CONFIG_PHYLIB
 #define CONFIG_PHY_ATHEROS
 
+#define CONFIG_CMD_PCI
+#ifdef CONFIG_CMD_PCI
+#define CONFIG_PCI
+#define CONFIG_PCI_PNP
+#define CONFIG_PCI_SCAN_SHOW
+#define CONFIG_PCIE_IMX
+#define CONFIG_PCIE_IMX_PERST_GPIO	IMX_GPIO_NR(2, 1)
+#define CONFIG_PCIE_IMX_POWER_GPIO	IMX_GPIO_NR(2, 0)
+#endif
+
 /* FLASH and environment organization */
 #define CONFIG_SYS_NO_FLASH