The definitions in ide/internal.h are duplicates, since ATAPI commands
actually come from SCSI.  Use the ones in scsi-defs.h and move the
missing ones there.  Two exceptions:

- MODE_PAGE_WRITE_PARMS conflicts with the "flexible disk geometry"
page in scsi-disk.c.  It is unused, so pick the latter.

- GPCMD_* is left in ide/internal.h, at least for now.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>