configs: omap3_logic: Remove USB Storage and enable CONFIG_BLK

With the pending requirement for CONFIG_BLK, this patch removes
the USB_STORAGE option which assumes that DM_USB is enabled, but isn't
yet available for the omap2340 musb glue among other issues.  Once
the USB issues are resolved, a future patch can enable them again.

Signed-off-by: Adam Ford <aford173@gmail.com>