imxwdt(4) on FreeBSD

The text 340b6fd4d02e, as FreeBSD 14.4-RELEASE, FreeBSD 14.3-RELEASE, FreeBSD 14.2-RELEASE, FreeBSD 14.1-RELEASE, FreeBSD 14.0-RELEASE shipped it.

device driver for the NXP i.MX5 and i.MX6 watchdog timer