drm/i915: Remove unused function parameter

The function parameter 'exclude' in funciton
i915_sw_fence_await_reservation() is not used.
Remove it.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922213916.12112-1-niranjana.vishwanathapura@intel.com