mcu: add Hydra Git input for Sayma MMC firmware

hydra/mcu.json

@@ -16,7 +16,8 @@
             "nixScripts": { "type": "git", "value": "https://git.m-labs.hk/M-Labs/nix-scripts.git", "emailresponsible": false },
             "stabilizerSrc": { "type": "git", "value": "git://github.com/quartiq/stabilizer.git", "emailresponsible": false },
             "thermostatSrc": { "type": "git", "value": "https://git.m-labs.hk/M-Labs/thermostat.git", "emailresponsible": false },
-            "humpbackDdsSrc": { "type": "git", "value": "https://git.m-labs.hk/M-Labs/humpback-dds.git", "emailresponsible": false }
+            "humpbackDdsSrc": { "type": "git", "value": "https://git.m-labs.hk/M-Labs/humpback-dds.git", "emailresponsible": false },
+            "saymaMmcSrc": { "type": "git", "value": "git://github.com/sinara-hw/openMMC sayma-devel", "emailresponsible": false }
         }
     }
 }