usb: dwc: dbm: indicates coming out of L1 with an interrupt

The DBM, in some versions, indicates via hardware interrupt
that a packet has been received on the DL (IN) path and that
the software should take the DWC controller out of L1 into L0.

Change-Id: I13180cffbe7040760842ebd345749d2a469adee2
Signed-off-by: Dov Levenglick <dovl@codeaurora.org>