accel/ivpu: Remove unneeded drm_driver declaration

Cleanup drm_driver declaration leftover.

Reviewed-by: Krystian Pradzynski <krystian.pradzynski@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231028133415.1169975-3-stanislaw.gruszka@linux.intel.com