Rename linkerconfig to linker_config

This makes it consistent with its inner props `gen_linker_config` and
`linker_config_srcs`

Test: m nothing --no-skip-soong-tests
Change-Id: I1bd7153e443697295ef226148a2c868223fbfda2
diff --git a/build/microdroid/Android.bp b/build/microdroid/Android.bp
index d9e39f0..7f23ae6 100644
--- a/build/microdroid/Android.bp
+++ b/build/microdroid/Android.bp
@@ -139,7 +139,7 @@
             ],
         },
     },
-    linkerconfig: {
+    linker_config: {
         gen_linker_config: true,
         linker_config_srcs: ["linker.config.json"],
     },