Configure serial console input device

Defaults to hvc0, which is the status quo and also the console device
Microdroid uses.
Allows configure to ttyS0, which is the actual device Ferrochrome uses.
Note: Need to update Ferrochrome vm_config.json

Bug: 335362012
Test: atest MicrodroidTestApp --test-filter com.android.microdroid.test.MicrodroidTests#testConsoleInputSupported'.*'
Test: Start vmlauncher_app and connect to VM console
Change-Id: I2e74abfbec2a9b7fb9b3642cc529eca4be9f0fdc
diff --git a/microdroid/microdroid.json b/microdroid/microdroid.json
index 00cedc8..e60c4ca 100644
--- a/microdroid/microdroid.json
+++ b/microdroid/microdroid.json
@@ -16,5 +16,6 @@
     }
   ],
   "memory_mib": 256,
+  "console_input_device": "hvc0",
   "platform_version": "~1.0"
 }