drm/i915/dvo: switch to kernel unsigned int types

We have fairly mixed uintN_t vs. uN usage throughout the driver, but try
to stick to kernel types at least where it's more prevalent.

v2: fix checkpatch warning on indentation

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180612095621.21101-1-jani.nikula@intel.com