schemas: firmware: add MP292XFirmware support

Add MP292XFirmware support to I2CVRFirmware, which enables defining
firmware metadata for MP292X voltage regulators.

Tested with a dummy config.

Change-Id: Iddd3de9b62ca15e7c746e679af5b0460aaf2ba41
Signed-off-by: Kevin Tung <kevin.tung.openbmc@gmail.com>
diff --git a/schemas/firmware.json b/schemas/firmware.json
index 3dfcdb3..a67b5f8 100644
--- a/schemas/firmware.json
+++ b/schemas/firmware.json
@@ -49,6 +49,7 @@
                         "XDPE1X2XXFirmware",
                         "ISL69269Firmware",
                         "MP2X6XXFirmware",
+                        "MP292XFirmware",
                         "MP297XFirmware",
                         "MP5998Firmware",
                         "MP994XFirmware",