drm/i915/vrr: Disable VRR TG in intel_vrr_transcoder_disable() only on always use_vrr...

drm/i915/vrr: Disable VRR TG in intel_vrr_transcoder_disable() only on always use_vrr_tg() platforms

Currently we always disable the VRR timing generator in
intel_vrr_transcoder_disable(). But doing so on !always_use_vrr_tg()
platforms is redundant since we've alreayd disabled the VRR timing
generator earlier in intel_vrr_disable(). Do the disable in
intel_vrr_transcoder_disable() only on always_on_vrr_tg() platforms.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20251020185038.4272-15-ville.syrjala@linux.intel.com
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>