configurations: x470d4u: add board config

Add configuration for the ASRock Rack X470D4U motherboard series which
is available in three known flavors.

Tested: Get data via busctl from entity-manager and check that ADC
values are correct.
```
root@x470d4u:~# busctl tree xyz.openbmc_project.EntityManager
`- /xyz
  `- /xyz/openbmc_project
    |- /xyz/openbmc_project/EntityManager
    `- /xyz/openbmc_project/inventory
      `- /xyz/openbmc_project/inventory/system
        `- /xyz/openbmc_project/inventory/system/board
          `- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/12V
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/1_05V_PROM_S5
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/2_5V_PROM
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/3V
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/3VSB
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/5V
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/5VSB
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/APU_VDDP
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/BMC
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/Chassis_Intrusion_Sensor
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/FAN1
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/FAN2
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/FAN3
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/FAN4
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/FAN5
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/FAN6
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/MB_FRU
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/SOC
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/VBAT
            |- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/VCCM
            `- /xyz/openbmc_project/inventory/system/board/ASRock_Rack_X470D4U/VCPU
```

Change-Id: Ice1d2b646ca96231f911d051687ffd91d0fdc7ba
Signed-off-by: Tan Siewert <tan@siewert.io>
diff --git a/configurations/meson.build b/configurations/meson.build
index bd810f7..7199e84 100644
--- a/configurations/meson.build
+++ b/configurations/meson.build
@@ -31,6 +31,7 @@
     'asrock/asrock_n3_xlarge_x86.json',
     'asrock/asrock_romed8hm3.json',
     'asrock/asrock_spc621d8hm3.json',
+    'asrock/asrock_x470d4u.json',
     'axx1p100hssi_aic.json',
     'axx2prthdhd.json',
     'bnp_baseboard.json',