usb: phy: mv-usb: fix usb_phy build errors

The driver was recently adapted to a core API change, but the
change was incomplete, missing out the suspend helper and
leaving an extraneous local variable around:

usb/phy/phy-mv-usb.c: In function 'mv_otg_update_state':
usb/phy/phy-mv-usb.c:341:18: warning: unused variable 'phy' [-Wunused-variable]

usb/phy/phy-mv-usb.c: In function 'mv_otg_suspend':
usb/phy/phy-mv-usb.c:861:16: error: 'struct usb_phy' has no member named 'state'

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: e47d9254 ("usb: move the OTG state from the USB PHY to the OTG structure")
Signed-off-by: Felipe Balbi <balbi@ti.com>