jfs: use time64_t for otime

The file creation time in the inode uses time_t which is defined
differently on 32-bit and 64-bit architectures and deprecated. The
representation in the inode uses an unsigned 32-bit number, but this
gets wrapped around after year 2038 when assigned to a time_t.

This changes the type to time64_t, so we can support the full range of
timestamps between 1970 and 2106 on 32-bit systems like we do on 64-bit
systems already, and matching what we do for the atime/ctime/mtime stamps
since the introduction of 64-bit timestamps in VFS.

Note: the otime stamp is not actually used anywhere at the moment in
the kernel, it is just set when writing a file, so none of this really
makes a difference unless we implement setting the btime field in the
getattr() callback.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>