hw/i386: Remove the deprecated machines 0.12 up to 0.15

hw/i386: Remove the deprecated machines 0.12 up to 0.15

These machines can't be used reliably for migration anymore, quoting
https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg04516.html :

"
 due to the introduction of the memory API, the firmware is not
 migrated correctly from source to destination.  On QEMU <1.3 the
 0xf0000-0xfffff area is basically a copy of the higher
 0xffff0000-0xffffffff area, while on more recent versions it is
 initialized with zeroes and the firmware copies from 0xffff0000 to
 0xf0000.  When you migrate from old to new QEMU, after reboot there's
 nothing at 0xf0000 and bugs ensue.
"

The pc-0.x machines have been marked as deprecated since QEMU v4.0, so
it is time to remove them now.

And while we're at it, mark the remaining pc-1.x machine types
as deprecated now, too, so that we finally only have "pc-i440fx"
and "pc-q35" machine types left (apart from the non-versioned
"isapc" and "microvm") once we remove them in a couple of releases.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20191209125248.5849-2-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>