usb: dwc2: Delete unused functionality

Deleted dwc2_hcd_dump_frrem() function, because it used undefined
parameters from dwc2_hsotg structure. The function body was in #ifdef
statement and was never compiled.

Also removed that parameters from dwc2_hsotg structure, which were
used only in dwc2_hcd_dump_frrem() function.

And also delete dwc2_sample_frrem macro, because without
dwc2_hcd_dump_frrem() function it's lose its purpose.

Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Grigor Tovmasyan <tovmasya@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>