Add the TMC PAT54PV

An ISA/VLB Socket 5 machine. Also makes KBC command A0 return 0x28 then 0 so that the BIOS can function.

src/machine/m_at_socket4_5.c

@@ -62,7 +62,27 @@ machine_at_excalibur_init(const machine_t *model)
 
     return ret;
 }
+int
+machine_at_pat54pv_init(const machine_t *model)
+{
+    int ret;
 
+    ret = bios_load_linear("roms/machines/pat54pv/pat54pv.bin",
+			   0x000f0000, 65536, 0);
+
+    if (bios_only || !ret)
+	return ret;
+
+    machine_at_common_init(model);
+
+    device_add(&opti5x7_device);
+    device_add(&keyboard_at_ami_device);
+    
+    if (fdc_type == FDC_INTERNAL)
+    device_add(&fdc_at_device);
+
+    return ret;
+}
 int
 machine_at_hot543_init(const machine_t *model)
 {