Adding a chardev backend for spice, where spice determines what
to do with it based on the name attribute given during chardev creation.
For usage by spice vdagent in conjunction with a properly named
virtio-serial device, and future smartcard channel usage.
Example usage:
qemu -device virtio-serial -chardev spicevmc,name=vdagent,id=vdagent \
-device virtserialport,chardev=vdagent,name=com.redhat.spice.0
v4->v5:
* add tracing events
* fix missing comma
* fix help string to show debug is optional
v3->v4:
* updated commit message
v1->v3 changes: (v2 had a wrong commit message)
* removed spice-qemu-char.h, folded into ui/qemu-spice.h
* removed dead IOCTL code
* removed comment
* removed ifdef CONFIG_SPICE from qemu-config.c and qemu-options.hx help.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
