microblaze: Add __ucmpdi2() helper function

Add missing __ucmpdi2 helper function.

Error log:
kernel/built-in.o: In function `print_graph_duration':
: undefined reference to `__ucmpdi2'
kernel/built-in.o: In function `print_graph_duration':
: undefined reference to `__ucmpdi2'

Based on MIPS code.

Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/lib/ucmpdi2.c b/arch/microblaze/lib/ucmpdi2.c
new file mode 100644
index 0000000..63ca105
--- /dev/null
+++ b/arch/microblaze/lib/ucmpdi2.c
@@ -0,0 +1,20 @@
+#include <linux/module.h>
+
+#include "libgcc.h"
+
+word_type __ucmpdi2(unsigned long long a, unsigned long long b)
+{
+	const DWunion au = {.ll = a};
+	const DWunion bu = {.ll = b};
+
+	if ((unsigned int) au.s.high < (unsigned int) bu.s.high)
+		return 0;
+	else if ((unsigned int) au.s.high > (unsigned int) bu.s.high)
+		return 2;
+	if ((unsigned int) au.s.low < (unsigned int) bu.s.low)
+		return 0;
+	else if ((unsigned int) au.s.low > (unsigned int) bu.s.low)
+		return 2;
+	return 1;
+}
+EXPORT_SYMBOL(__ucmpdi2);