drivers: depend on HAS_IOMEM for devm_platform_ioremap_resource()

We only build devm_ioremap_resource() if HAS_IOMEM is selected, so this
dependency must cascade down to devm_platform_ioremap_resource().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>