drm/i915/glk: Remove MODULE_FIRMWARE() tag from Geminilake's DMC

Geminilake's DMC is not yet available in the linux-firmware repository.
To prevent userspace tools such as mkinitramfs to complain about
missing firmware, remove the MODULE_FIRMWARE() tag for now.

Fixes: dbb28b5c ("drm/i915/DMC/GLK: Load DMC on GLK")
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <drm-intel-fixes@lists.freedesktop.org>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170306085651.14008-1-ander.conselvan.de.oliveira@intel.com