ANDROID: fuzz: Rename libfdt_fuzzer.cpp to .c

Change cpp to c file ahead of further extensions to the fuzzing test
harness. This simplifies building afl-fuzz or with just C tools, but
could be made C++ again if needed in the future.

Test: build and ran libFuzzer test
Change-Id: Ibc7edc8834fa71d4bbabac826efccb49d8a1be38
Merged-In: I8873883ab5b91f36b707cd9d05856aa4c9c222bd

fuzzing/Android.bp

@@ -6,7 +6,7 @@ package {
 cc_fuzz {
     name: "libfdt_fuzzer",
     srcs: [
-        "libfdt_fuzzer.cpp",
+        "libfdt_fuzzer.c",
     ],
     static_libs: [
         "libfdt",

fuzzing/libfdt_fuzzer.c

@@ -29,7 +29,7 @@ void walk_device_tree(const void *device_tree, int parent_node) {
 
 // Information on device tree is available in external/dtc/Documentation/
 // folder.
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   // Non-zero return values are reserved for future use.
   if (size < FDT_V17_SIZE) return 0;