qga: Correct loop count in qmp_guest_get_vcpus()

qga: Correct loop count in qmp_guest_get_vcpus()

The guest-get-vcpus returns incorrect vcpu info in case we hotunplug vcpus(not
the last one).
e.g.:
A VM has 4 VCPUs: cpu0 + 3 hotunpluggable online vcpus(cpu1, cpu2 and cpu3).
Hotunplug cpu2,  Now only cpu0, cpu1 and cpu3 are present & online.

./qmp-shell /tmp/qmp-monitor.sock
(QEMU) query-hotpluggable-cpus
{"return": [
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu2", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
 "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
]}

(QEMU) device_del id=cpu2
{"return": {}}

(QEMU) query-hotpluggable-cpus
{"return": [
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
 "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
 "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
]}

Before:
./qmp-shell -N /tmp/qmp-ga.sock
Welcome to the QMP low-level shell!
Connected
(QEMU) guest-get-vcpus
{"return": [
{"online": true, "can-offline": false, "logical-id": 0},
{"online": true, "can-offline": true, "logical-id": 1}]}

After:
./qmp-shell -N /tmp/qmp-ga.sock
Welcome to the QMP low-level shell!
Connected
(QEMU) guest-get-vcpus
{"return": [
{"online": true, "can-offline": false, "logical-id": 0},
{"online": true, "can-offline": true, "logical-id": 1},
{"online": true, "can-offline": true, "logical-id": 3}]}

Signed-off-by: Lin Ma <lma@suse.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
*fix build breakage by using PRId64 for sscanf
Signed-off-by: Michael Roth <michael.roth@amd.com>