Mips: remove arch-specific atexit.h

Change-Id: I687ff4ead6c5e81db44782bf851cb84f87bfe085
diff --git a/libc/arch-mips/bionic/crtbegin.c b/libc/arch-mips/bionic/crtbegin.c
index 28e8817..50e9eeb 100644
--- a/libc/arch-mips/bionic/crtbegin.c
+++ b/libc/arch-mips/bionic/crtbegin.c
@@ -91,4 +91,4 @@
 );
 
 #include "../../arch-common/bionic/__dso_handle.h"
-#include "atexit.h"
+#include "../../arch-common/bionic/atexit.h"