Revert "UPSTREAM: usb: dwc3: gadget: disable XFER_NOT_READY"

Revert "UPSTREAM: usb: dwc3: gadget: disable XFER_NOT_READY"

This reverts commit 2a1f2d1e890354821dd8a8e621998d532185061d.

Refer to DWC3 databook, Table 7-7 Device Endpoint-n Events(DEPEVT),
XferNotReady is generated when the core responds NRDY to the host
on the USB. It is useful in the beginning of a transfer when
software wants to wait for the host to start polling the endpoint
before setting up TRBs. And also refer to 8.2.4 Transfer Setup
Recommendations, when using on-demand transfers, the XferNotRead
event must be enabled.

TEST=Set usb gadget work as RNDIS, connect to win7/win10, check
the RNDIS function

Change-Id: I091cd3ff4a3c93e6cc02fcc6714511c8989786bf
Signed-off-by: Wu Liang feng <wulf@rock-chips.com>