usb: musb: select GENERIC_PHY instead of depending on it

The kconfig symbol GENERIC_PHY says:
  All the users of this framework should select this config.
and around 136 out of 138 drivers do so, so change USB_MUSB_MEDIATEK
to do so also.

This (also) fixes a long circular dependency problem for an upcoming
patch.

Fixes: 0990366b ("usb: musb: Add support for MediaTek musb controller")
Cc: Bin Liu <b-liu@ti.com>
Cc: Min Guo <min.guo@mediatek.com>
Cc: Yonglong Wu <yonglong.wu@mediatek.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-mediatek@lists.infradead.org
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20211005235747.5588-1-rdunlap@infradead.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/Kconfig

@@ -120,7 +120,7 @@ config USB_MUSB_MEDIATEK
 	tristate "MediaTek platforms"
 	depends on ARCH_MEDIATEK || COMPILE_TEST
 	depends on NOP_USB_XCEIV
-	depends on GENERIC_PHY
+	select GENERIC_PHY
 	select USB_ROLE_SWITCH
 
 comment "MUSB DMA mode"