drm/xe: Remove dead clock code

xe_gt_clock_cycles_to_ns() is not called from anywhere after PMU
handling was removed in commit 90a8b23f ("drm/xe/pmu: Remove PMU
from Xe till uapi is finalized"). Drop it.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240408151312.2100304-1-lucas.demarchi@intel.comSigned-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

drivers/gpu/drm/xe/xe_gt_clock.c

@@ -78,8 +78,3 @@ int xe_gt_clock_init(struct xe_gt *gt)
 	gt->info.reference_clock = freq;
 	return 0;
 }
-
-u64 xe_gt_clock_cycles_to_ns(const struct xe_gt *gt, u64 count)
-{
-	return DIV_ROUND_CLOSEST_ULL(count * NSEC_PER_SEC, gt->info.reference_clock);
-}

drivers/gpu/drm/xe/xe_gt_clock.h

@@ -11,5 +11,5 @@
 struct xe_gt;
 
 int xe_gt_clock_init(struct xe_gt *gt);
-u64 xe_gt_clock_cycles_to_ns(const struct xe_gt *gt, u64 count);
+
 #endif