drm/i915: remove duplicate MODULE_LICENSE definition

Multiple definitions show up multiple times in modinfo output.

There's already an identical one in i915_drv.c along with other MODULE_*
definitions, so drop the lone one in intel_fbdev.c.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>