ARC: reset: Only build on archs that have IOMEM

This avoids the error:
drivers/reset/reset-hsdk-v1.o: In function `hsdkv1_reset_probe':
/home/thomas/git/linux/drivers/reset/reset-hsdk-v1.c:101: undefined
reference to `devm_ioremap_resource'
collect2: error: ld returned 1 exit status

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>