Remove __BIONIC_LEGACY_INLINE.

Don't use the same declaration to declare both static and non-static
functions, to make life easier for versioner.

(Also, remove __BIONIC_LEGACY_INLINE from two functions in termios.h
that weren't actually legacy inlines.)

Bug: http://b/30170081
Change-Id: Ibb73377d77a2b4cee016289b7c46a01452e45fae
diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index 0a999e4..a65f27a 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -177,7 +177,12 @@
 }
 #endif /* defined(__BIONIC_FORTIFY) */
 
-__BIONIC_LEGACY_INLINE int mkfifo(const char*, mode_t);
+#if __ANDROID_API__ >= 21
+int mkfifo(const char*, mode_t);
+#else
+// Implemented as a static inline before 21.
+#endif
+
 extern int mkfifoat(int, const char*, mode_t) __INTRODUCED_IN(23);
 
 extern int fchmodat(int, const char*, mode_t, int);