drm/i915/skl: Fix DMC API version in firmware file name

04 is the minor version. API version is ver1.
So let's follow same scheme used on published version at 01.org.

If really needed the minor version a follow-up updated will be
done. But for now we need to move fwd and unblock end users.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>