from userland to get the debugging definitions.
New device names are "{tty|cua}A$(card)$(port)[.init|.lock]" Put a portname in the port structure if SI_DEBUG is defined to avoid need to inspect minor number to construct name.. Constify some strings. Remove duplicated DBG_ #defines.
Split out the bus attachments so the impact of the bus xxxvar.h files with the inline macros for the ivars are confined to one file each.
