Add missing typedefs for C compat.

Bug: https://github.com/android/ndk/issues/1920
Test: clang --sysroot out/soong/ndk/sysroot
          out/soong/ndk/sysroot/usr/include/**/*.h

Change-Id: I2fc435c16bc8df77c2ab0754f2cc43d9aa717de8
diff --git a/include/android/thermal.h b/include/android/thermal.h
index fa168cd..7f9d2ed 100644
--- a/include/android/thermal.h
+++ b/include/android/thermal.h
@@ -85,6 +85,7 @@
     /** Need shutdown immediately. */
     ATHERMAL_STATUS_SHUTDOWN = 6,
 };
+typedef enum AThermalStatus AThermalStatus;
 
 /**
  * An opaque type representing a handle to a thermal manager.
@@ -240,6 +241,7 @@
     float headroom;
     AThermalStatus thermalStatus;
 };
+typedef struct AThermalHeadroomThreshold AThermalHeadroomThreshold;
 
 /**
  * Gets the thermal headroom thresholds for all available thermal status.