usb: musb: davinci: Fix build breakage

This appears to have been broken by
commit 5cfb19ac604a68c030b245561f575c2d1bac1d49
(ARM: davinci: streamline sysmod access)

For now, fix by hardcoding USB_PHY_CTRL and DM355_DEEPSLEEP

Tested on DM365 with defconfig changes.

Signed-off-by: Jon Povey <jon.povey@racelogic.co.uk>
Acked-by: Sekhar Nori <nsekhar@ti.com>
CC: Felipe Balbi <balbi@ti.com>
Cc: <stable@vger.kernel.org> # v3.4.x
Signed-off-by: Felipe Balbi <balbi@ti.com>