drm/i915/vrr: Annotate some functions with "hw"

drm/i915/vrr: Annotate some functions with "hw"

intel_vrr_fixed_rr_*() return values that have had the TGL
SCL adjustment applied to them. So we should indicate that these
values are only really useful when fed to the hardware. Add
a "_hw_" indicator to the function names to reflect that fact.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250917203446.14374-5-ville.syrjala@linux.intel.com
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>