bootdevice: move code about bootorder from vl.c to bootdevice.c

First, we can downsize vl.c, make it simpler by
little and little. Second, I can maintain those code
and make some improvement.

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
bootdevice: add Error **errp argument for validate_bootdevices()

It will be useful for checking when we change traditional
boot order dynamically and propagate error message
to the monitor.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
bootdevice: add Error **errp argument for qemu_boot_set()

It will be useful for checking when we change traditional
boot order dynamically and propagate error message
to the monitor.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
bootdevice: add validate check for qemu_boot_set()

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
bootdevice: add Error **errp argument for QEMUBootSetHandler

It will be useful for checking when we change traditional
boot order dynamically and propagate error message
to the monitor.
For x86 architecture, we pass &local_err to set_boot_dev()
when vm startup in pc_coms_init().

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Blue Swirl <blauwirbel@gmail.com>
Cc: qemu-ppc@nongnu.org
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Merge remote-tracking branch 'remotes/gonglei/tags/bootdevice-next-20141222' into staging

bootdevice: Refactor and improvement

# gpg: Signature made Mon 22 Dec 2014 06:44:08 GMT using RSA key ID DDE30FBB
# gpg: Can't check signature: public key not found

* remotes/gonglei/tags/bootdevice-next-20141222:
  bootdevice: add Error **errp argument for QEMUBootSetHandler
  bootdevice: add validate check for qemu_boot_set()
  bootdevice: add Error **errp argument for qemu_boot_set()
  bootdevice: add Error **errp argument for validate_bootdevices()
  bootdevice: move code about bootorder from vl.c to bootdevice.c

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>