Drop the bus reset hold delay back down to 25us. The 250us

Drop the bus reset hold delay back down to 25us.  The 250us
value slipped in from a debugging session.

Add AHC_LSCBS_ENABLED and AHC_SCB_CONFIG_USED ahc_flags which
allow for some code to move to the core.

Remove extern for ahc_syncrates[].  The OSMs no longer need
direct access to this array.

Add serial eeprom field to the ahc softc.

Prototype ahc_search_untagged_queues() and ahc_print_register().

Convert to AHC_SHOW_XXX debug option format.