nilfs2: Switch to use %ptTs

nilfs2: Switch to use %ptTs

Use %ptTs instead of open coded variant to print contents
of time64_t type in human readable form.

Use sysfs_emit() at the same time in the changed functions.

Cc: Ryusuke Konishi <[email protected]>
Cc: [email protected]
Signed-off-by: Andy Shevchenko <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]