pc: acpi: fix pvpanic regression

Commit cd61cb2e  pc: acpi-build: generate pvpanic device description dynamically

introduced regression changing pvpanic device HID from
QEMU0001 to QEMU0002.
Fix AML generated code so that pvpanic device
would keep its original HID. i.e. QEMU0001

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reported-by: Gal Hammer <ghammer@redhat.com>
Message-Id: <1427717907-25027-1-git-send-email-imammedo@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>