Convert CONFIG_USB_MUSB_HCD et al to Kconfig

This converts the following to Kconfig:
   CONFIG_USB_MUSB_HCD
   CONFIG_USB_MUSB_UDC
   CONFIG_USB_DAVINCI
   CONFIG_USB_OMAP3
   CONFIG_USB_DA8XX
   CONFIG_USB_AM35X

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/configs/nokia_rx51_defconfig b/configs/nokia_rx51_defconfig
index 9057811..570bb3f 100644
--- a/configs/nokia_rx51_defconfig
+++ b/configs/nokia_rx51_defconfig
@@ -26,6 +26,10 @@
 CONFIG_MMC_OMAP_HS=y
 CONFIG_SYS_NS16550=y
 CONFIG_OMAP3_SPI=y
+CONFIG_USB=y
+CONFIG_USB_MUSB_HCD=y
+CONFIG_USB_MUSB_UDC=y
+CONFIG_USB_OMAP3=y
 CONFIG_VIDEO=y
 CONFIG_CFB_CONSOLE_ANSI=y
 # CONFIG_VGA_AS_SINGLE_DEVICE is not set