Ack! Only 4 uarts with FC6!

[Tom Horsley <tomhorsley adelphia net>]

Lo these many years, the kernel parameter 8250.nr_uarts=9 has
been functioning perfectly to give me access to all 8 ports
on my byterunner board as well as the one uart on the motherboard.

Now with FC6 (the Xen kernel anyway), I get an error claiming
that is an unrecognized option, and I only see 4 uarts in /dev.

This sound like something I should report as a kernel bug?
(Or has the syntax just changed out from under me?)