The precision clock synthesizer support broke the driver on the QorIQ
P1020. On this device the Alternate Function Register is accessed with
DLAB == 1 instead of the FIFO Control Register (FCR). Restructure the
code to account for this.
Set the FIFO control register while DLAB == 1 in the line control
register. At least on the QorIQ T4240 the driver still works with the
re-ordered FIFO control register access.
