i965/clear: Remove an early return in fast_clear_depth
Reduce complexity and allow the next patch to delete some code. With
this change, clear operations will still be skipped and setting the
aux_state will cause no side-effects.
Remove the associated comment which implies an early return.
Reviewed-by: Rafael Antognolli <email@example.com>
Reviewed-by: Jason Ekstrand <firstname.lastname@example.org>