fat: remove time truncations in vfat_create/vfat_mkdir

All the timestamps in vfat_create() and vfat_mkdir() come from
fat_time_fat2unix() which ensures time granularity.  We don't need to
truncate them to fit FAT's format.

Moreover, fat_truncate_crtime() and fat_timespec64_trunc_10ms() are also
removed because there is no caller anymore.

Link: https://lkml.kernel.org/r/20220503152536.2503003-4-cccheng@synology.com


Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>