compiler, clang: properly override 'inline' for clang

BugLink: https://bugs.launchpad.net/bugs/1790884

commit 6d53cefb upstream.

Commit abb2ea7d ("compiler, clang: suppress warning for unused
static inline functions") just caused more warnings due to re-defining
the 'inline' macro.

So undef it before re-defining it, and also add the 'notrace' attribute
like the gcc version that this is overriding does.

Maybe this makes clang happier.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

include/linux/compiler-clang.h

@@ -21,4 +21,5 @@
  * -Wunused-function.  This turns out to avoid the need for complex #ifdef
  * directives.  Suppress the warning in clang as well.
  */
-#define inline inline __attribute__((unused))
+#undef inline
+#define inline inline __attribute__((unused)) notrace