drm/i915/uc: Fetch uC firmware in init_early

We were fetching uC firmwares in separate uc_init_fw step, while
there is no reason why we can't fetch them during init_early.
This will also simplify upcoming patches, as size of the firmware
may be used for register initialization.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180323123451.59244-2-michal.wajdeczko@intel.com