dwc3: gadget: Remove soft reset as part of gadget run_stop

Soft reset of the core before setting the run stop
bit of the core is not suggested.
So, remove the soft reset of the core as part of
the run_stop operation.

Change-Id: Ib87176d8036a27cc7e0a5790b293ee79811e4734
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>