usb: gadget: renesas_usbhs: move usbhs_usbreq_get/set_val() to common.c

usbhs_usbreq_get/set_val() functions were in pipe.c file,
but it is irrelevant to pipe.
this patch move it to common.c

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>