UPSTREAM: usb: dwc2: gadget: Remove unnecessary code

UPSTREAM: usb: dwc2: gadget: Remove unnecessary code

This chunk is not needed here. There is no functionality
depend on this, so if no-op, I think we do not need to have
this interrupt unmasked.

Change-Id: I74a0861ce66e23888c001b7cf1833b7cce715362
Tested-by: John Keeping <john@metanate.com>
Signed-off-by: Vardan Mikayelyan <mvardan@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Huang, Tao <huangtao@rock-chips.com>
(cherry picked from commit 7c01b99154c5819bb811100738880a1341bca64a)