lib/ucs2_string: Speed up ucs2_utf8size()

No need to calculate the string length on every loop iteration.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Peter Jones <pjones@redhat.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c
index f0b323a..ae8d249 100644
--- a/lib/ucs2_string.c
+++ b/lib/ucs2_string.c
@@ -56,7 +56,7 @@
 	unsigned long i;
 	unsigned long j = 0;
 
-	for (i = 0; i < ucs2_strlen(src); i++) {
+	for (i = 0; src[i]; i++) {
 		u16 c = src[i];
 
 		if (c >= 0x800)