drm/vmwgfx: Drop mksstat_init_record fn as currently unused

This internal helper handles a type of mksstat event counter
which is currently unused. Remove the routine to avoid compile
warnings.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Martin Krastev <krastevm@vmware.com>
Reviewed-by: Maaz Mombasawala <mombasawalam@vmware.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230321020949.335012-1-zack@kde.org