drm/i915/gt: replace cache_clflush_range

Replace all occurrence of cache_clflush_range with drm_clflush_virt_range.
This will prevent compile errors on non-x86 platforms.

Signed-off-by: Michael Cheng <michael.cheng@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321223819.72833-6-michael.cheng@intel.com