schemas: firmware: add MP297XFirmware support

Add MP297XFirmware support to I2CVRFirmware, which enables defining
firmware metadata for MP297X voltage regulators.

In [1], support for updating MP297X VR devices was introduced.

[1] https://gerrit.openbmc.org/c/openbmc/phosphor-bmc-code-mgmt/+/82948

Tested with a dummy config.

Change-Id: Iac2e046a43bd409b90e19f86d0ac6057d65b5f63
Signed-off-by: Kevin Tung <kevin.tung.openbmc@gmail.com>
diff --git a/schemas/firmware.json b/schemas/firmware.json
index 68706c9..bdf4c5c 100644
--- a/schemas/firmware.json
+++ b/schemas/firmware.json
@@ -31,7 +31,8 @@
                     "enum": [
                         "XDPE1X2XXFirmware",
                         "ISL69269Firmware",
-                        "MP2X6XXFirmware"
+                        "MP2X6XXFirmware",
+                        "MP297XFirmware"
                     ]
                 },
                 "Bus": {