drm/i915: extract intel_bw_check_qgv_points()

Extract intel_bw_check_qgv_points() from intel_bw_atomic_check
to facilitate future platform variations in handling SAGV
configurations.

Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606093509.221709-5-vinod.govindapillai@intel.com