cifs: Use cifs_autodisable_serverino() for disabling CIFS_MOUNT_SERVER_INUM in readdir.c

In all other places is used function cifs_autodisable_serverino() for
disabling CIFS_MOUNT_SERVER_INUM mount flag. So use is also in readir.c
_initiate_cifs_search() function. Benefit of cifs_autodisable_serverino()
is that it also prints dmesg message that server inode numbers are being
disabled.

Fixes: ec06aedd ("cifs: clean up handling when server doesn't consistently support inode numbers")
Fixes: f534dc99 ("cifs: clear server inode number flag while autodisabling")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>