ide: qdev property for BIOS CHS translation

ide: qdev property for BIOS CHS translation

This isn't quite orthodox.  CHS translation is firmware configuration,
communicated via the RTC's CMOS RAM, not a property of the disk.  But
it's best to treat it just like geometry anyway.

Maintain backward compatibility exactly like for geometry: fall back
to DriveInfo's translation, set with -drive trans=...

Bonus: info qtree now shows the translation.  Except when it shows
"auto": that's resolved by pc_cmos_init_late().  To be addressed
shortly.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>