Revert "usb: dwc3: gadget: Avoid starting DWC3 gadget during UDC unbind"

This reverts commit b83692fe which is
commit 8217f07a upstream.

It breaks the kernel ABI and will be brought back in an abi-safe way in
a later commit.

Bug: 161946584
Bug: 200287549
Cc: Wesley Cheng <wcheng@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ib9a113d36bc784b243e5a1b168a8c7470992c8ff