drm/i915/uc: Move FW size sanity check back to fetch

While we need to know WOPCM size to do this sanity check, it has more to
do with FW than with WOPCM. Let's move the check to fetch phase, it's
not like WOPCM is going to grow in the meantime.

v2: rebased
v3: use __intel_uc_fw_get_upload_size (Daniele)

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jackie Li <yaodong.li@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190816105501.31020-2-michal.wajdeczko@intel.com