pc: Don't set hw_version on pc-*-2.5

Now that qemu_hw_version() returns a fixed "2.5+" string instead
of QEMU_VERSION, we don't need to set hw_version on pc-*-2.5
explicitly.
Suggested-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/i386/pc_piix.c

@@ -472,7 +472,6 @@ static void pc_i440fx_machine_options(MachineClass *m)
 static void pc_i440fx_2_5_machine_options(MachineClass *m)
 {
     pc_i440fx_machine_options(m);
-    m->hw_version = QEMU_VERSION;
     m->alias = "pc";
     m->is_default = 1;
 }

hw/i386/pc_q35.c

@@ -373,7 +373,6 @@ static void pc_q35_machine_options(MachineClass *m)
 static void pc_q35_2_5_machine_options(MachineClass *m)
 {
     pc_q35_machine_options(m);
-    m->hw_version = QEMU_VERSION;
     m->alias = "q35";
 }