fix(st-usb): replace redundant checks with asserts

Returning enum usb_status in an enum usb_action function is wrong as
they have different meanings. However, usb_dwc2_ep0_out_start() and
usb_dwc2_activate_setup() only return USBD_OK so we will never get to
there. Replace these checks with asserts in case the code changes in
future.

This also silences a warning when compiling with -Wextra.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I73dfd5c189a357544c15ceb3f4268da82ce272b9
1 file changed