usb: renesas_usbhs: Assert/de-assert reset signals on suspend/resume

usb: renesas_usbhs: Assert/de-assert reset signals on suspend/resume

The Renesas RZ/G3S SoC supports a power-saving mode in which power to most
SoC components is turned off, including the USB subsystem.

To properly restore from such a state, the reset signal needs to be
asserted/de-asserted during suspend/resume. Add reset assert/de-assert on
suspend/resume.

The resume code has been moved into a separate function to allow reusing
it in case reset_control_assert() from suspend fails.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20251106143625.3050119-5-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>