pmac_zilog wasn't properly updating port->timeout, thus broke with serial
console.  I'm not sure if that timeout thing was added recently or not,
since the driver used to work fine.  This patch fixes that, and adds some
proper SYSRQ support.  By default, BREAK is used for sysrq, though some
Apple zilog's seem to have non-working BREAK detection logic, thus the
driver has a #define option you can manually enable when debugging to do
SYSRQ with ctrl-O instead (like pSeries virtual consoles).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>