This change removes a bogus error message from the IOC4 serial driver
interrupt handler.

This error message is bogus for two reasons.  First, it can never occur
given that current code takes care to initialize IOC4 in such a way that
these "unknown" interrupts could never occur.  Second, this code fails to
take into account that other drivers can share the IOC4 interrupt mechanism
through SA_SHIRQ, and thus this driver is not in-fact "all-knowing".

Finally, this error message triggers every time some "unknown" interrupt
occurs -- it's not rate limited or repetition limited in any way, thereby
effectively denying use of the console device.  Given its bogosity in the
first place, it's best to just get rid of it entirely.

Acked-by: Pat Gefre <pfg@sgi.com>
Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>