[PARISC] Update pdc console from parisc tree

Get rid of some unnecessary includes
Remove a layer of macro indirection around pdc_console_device
Delete pdc_console_die() as it is unused
Avoid double-printing on panic by clearing CON_PRINTBUFFER rather than
setting con_start to be log_end
Make con_start and log_end static again

Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>