We read the bus end value from the _CRS method. On some systems we need
to further limit it based on the MCFG table.
Support this by setting a default value, then update it if needed in the
_CRS table, and finally reduce it if it is past the end of the MCFG tabel.
This will allow for both systems that use either method to encode this
This partially reverts r347929, removing the error printf.