Convert CONFIG_TWL4030_USB to Kconfig

This converts the following to Kconfig:
   CONFIG_TWL4030_USB

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/configs/omap3_zoom1_defconfig b/configs/omap3_zoom1_defconfig
index db867b1..1a915c5 100644
--- a/configs/omap3_zoom1_defconfig
+++ b/configs/omap3_zoom1_defconfig
@@ -44,5 +44,6 @@
 CONFIG_USB=y
 CONFIG_USB_MUSB_UDC=y
 CONFIG_USB_OMAP3=y
+CONFIG_TWL4030_USB=y
 CONFIG_FAT_WRITE=y
 CONFIG_OF_LIBFDT=y