microblaze: ftrace: Remove check of obsolete variable function_trace_stop

Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.

Link: http://lkml.kernel.org/r/53C8D82B.4030204@monstr.eu

Tested-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

arch/microblaze/kernel/mcount.S

@@ -91,11 +91,6 @@ ENTRY(ftrace_caller)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 	SAVE_REGS
 	swi	r15, r1, 0;
-	/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST begin of checking */
-	lwi	r5, r0, function_trace_stop;
-	bneid	r5, end;
-	nop;
-	/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 #ifndef CONFIG_DYNAMIC_FTRACE
 	lwi	r5, r0, ftrace_graph_return;