usb: dwc3: ep0: Handle requests greater than wMaxPacketSize

To allow ep0 out transfers of upto bounce buffer size
instead of maxpacketsize, use the transfer size as multiple
of ep0 maxpacket size.

Cc: stable@vger.kernel.org
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Partha Basak <p-basak2@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>