sh: Fix up uninitialized variable warning in dwarf unwinder.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 718286b..4d8c7bd 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -902,7 +902,7 @@
 	u32 entry_type;
 	void *p, *entry;
 	int count, err = 0;
-	unsigned long len;
+	unsigned long len = 0;
 	unsigned int c_entries, f_entries;
 	unsigned char *end;