phy: kconfig: add depends on "USB_PHY" to OMAP_USB2 and TWL4030_USB

Fixes
warning: (OMAP_USB2 && TWL4030_USB) selects USB_PHY which has unmet
direct dependencies (USB_SUPPORT)
that shows up while disabling USB_SUPPORT from menuconfig.

Reported-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>