Convert CONFIG_OMAP3_SPI to Kconfig

This converts the following to Kconfig:
   CONFIG_OMAP3_SPI

Signed-off-by: Adam Ford <aford173@gmail.com>
[trini: Minor comment tweaks]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/pepper_defconfig b/configs/pepper_defconfig
index a7e0574..0556437 100644
--- a/configs/pepper_defconfig
+++ b/configs/pepper_defconfig
@@ -45,5 +45,6 @@
 CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_NETDEVICES=y
 CONFIG_SYS_NS16550=y
+CONFIG_OMAP3_SPI=y
 CONFIG_FAT_WRITE=y
 CONFIG_OF_LIBFDT=y