microblaze: ftrace: enable HAVE_FUNCTION_TRACE_MCOUNT_TEST

Implement MCOUNT_TEST in asm code - it is faster than use
generic code

Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index 18003ca..cccf3ad 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -7,6 +7,7 @@
 	def_bool y
 	select HAVE_LMB
 	select HAVE_FUNCTION_TRACER
+	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	select USB_ARCH_HAS_EHCI
 	select ARCH_WANT_OPTIONAL_GPIOLIB