DRM: ingenic: Use devm_platform_ioremap_resource

Simplify a bit the probe function by using the newly introduced
devm_platform_ioremap_resource(), instead of having to call
platform_get_resource() followed by devm_ioremap_resource().

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190627182114.27299-1-paul@crapouillou.net


# *** extracted tags ***
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>