sh: update r2d defconfigs with usb, spi and rtc

Update the defconfigs for r2d-plus and r2d-1 since we now have new drivers
for sm501 usb, spi-over-sci and epson r9701 rtc in mainline.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>