usb: dwc2: gadget: initialize max_speed from params

DWC2 may be paired with a full-speed PHY which is not capable of
high-speed operation.  Report this correctly to the gadget core by
setting max_speed from the core parameters.

Prior to commit 5324bad6 ("usb: dwc2: gadget: implement
udc_set_speed()") this didn't cause the hardware to be configured
incorrectly, although the speed may have been reported incorrectly.  But
after that commit params.speed is updated based on a value passed in by
the gadget core which may set it to a faster speed than is supported by
the hardware.  Initialising the max_speed parameter ensures the speed
passed to dwc2_gadget_set_speed() will be one supported by the hardware.

Fixes: 5324bad6 ("usb: dwc2: gadget: implement udc_set_speed()")
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Signed-off-by: John Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20220106115731.1473909-1-john@metanate.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>