vt_ioctl: change VT_RESIZEX ioctl to check for error return from vc_resize()

vc_resize() can return with an error after failure. Change VT_RESIZEX ioctl
to save struct vc_data values that are modified and restore the original
values in case of error.

Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Cc: stable <stable@vger.kernel.org>
Reported-by:  <syzbot+38a3699c7eaf165b97a6@syzkaller.appspotmail.com>
Link: https://lore.kernel.org/r/1596213192-6635-2-git-send-email-george.kennedy@oracle.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>