usb: dwc3: remove dwc3_gadget_init_hw_endpoints

A previous patch in the series reduces the number of  callsites of
dwc3_gadget_init_hw_endpoints from two to one. This patch removes the
redundant step of wrappering one function in the other, which can be done
by adding a parameter to dwc3_gadget_init_endpoints and moving the
linked-list initialization of dwc->gadet.ep_list.

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>