Fix MIPS build.

Warnings are errors for all home-grown bionic code, and the arch-specific
code now counts as home-grown bionic code (it was mistakenly counted as
"not ours" before).

Change-Id: I9c6a881b0dc596bae7dfe112c5c189e073800a3a
diff --git a/libc/arch-mips/bionic/cacheflush.c b/libc/arch-mips/bionic/cacheflush.cpp
similarity index 97%
rename from libc/arch-mips/bionic/cacheflush.c
rename to libc/arch-mips/bionic/cacheflush.cpp
index 2b03eee..7955dd6 100644
--- a/libc/arch-mips/bionic/cacheflush.c
+++ b/libc/arch-mips/bionic/cacheflush.cpp
@@ -55,8 +55,7 @@
 #endif
 
 /* This is the Android signature */
-int cacheflush (long start, long end, long flags)
-{
+int cacheflush (long start, long end, long /*flags*/) {
 	if (end < start) {
 		/*
 		 * It looks like this is really MIPS style cacheflush call