objtool: Add fortify_panic as __noreturn function

CONFIG_FORTIFY_SOURCE=y implements fortify_panic() as a __noreturn function,
so objtool needs to know about it too.
Suggested-by: Daniel Micay <danielmicay@gmail.com>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1497532835-32704-1-git-send-email-jpoimboe@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

tools/objtool/builtin-check.c

@@ -192,7 +192,8 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func,
 		"complete_and_exit",
 		"kvm_spurious_fault",
 		"__reiserfs_panic",
-		"lbug_with_loc"
+		"lbug_with_loc",
+		"fortify_panic",
 	};
 
 	if (func->bind == STB_WEAK)