reset: intel: add unspecified HAS_IOMEM dependency

Currently CONFIG_RESET_INTEL_GW=y implicitly depends on
CONFIG_HAS_IOMEM=y; consequently, on architectures without IOMEM we get
the following build error:

/usr/bin/ld: drivers/reset/reset-intel-gw.o: in function `intel_reset_probe':
drivers/reset/reset-intel-gw.c:185: undefined reference to `devm_platform_ioremap_resource'

Fix the build error by adding the unspecified dependency.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>