drm/i915/gt: use get_reset_domain() helper

We dont need to implement reset_domain in intel_engine
_setup(), but can be done as a helper. Implemented as
engine->reset_domain = get_reset_domain().

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220217123223.748184-1-tejaskumarx.surendrakumar.upadhyay@intel.com