drm/i915/guc: Kick tasklet after queuing a request

Kick tasklet after queuing a request so it submitted in a timely manner.

Fixes: 3a4cdf19 ("drm/i915/guc: Implement GuC context operations for new inteface")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-9-matthew.brost@intel.com