usb: phy: fix driver dependencies

both isp1301-omap and fsl_usb2_otg drivers
depend on usb_bus_start_enum() which is only
defined if CONFIG_USB != n. There is a problem,
however, where both those drivers could be
statically linked, while CONFIG_USB=m.

Fix the problem by fixing driver dependency.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/Kconfig

@@ -19,8 +19,9 @@ config AB8500_USB
 	  in host mode, low speed.
 
 config FSL_USB2_OTG
-	bool "Freescale USB OTG Transceiver Driver"
+	tristate "Freescale USB OTG Transceiver Driver"
 	depends on USB_EHCI_FSL && USB_FSL_USB2 && PM_RUNTIME
+	depends on USB
 	select USB_OTG
 	select USB_PHY
 	help
@@ -29,6 +30,7 @@ config FSL_USB2_OTG
 config ISP1301_OMAP
 	tristate "Philips ISP1301 with OMAP OTG"
 	depends on I2C && ARCH_OMAP_OTG
+	depends on USB
 	select USB_PHY
 	help
 	  If you say yes here you get support for the Philips ISP1301