efi_loader: rename utf16_strlen, utf16_strnlen

The function names utf16_strlen() and utf16_strnlen() are misnomers.
The functions do not count utf-16 characters but non-zero words.
So let's rename them to u16_strlen and u16_strnlen().

In utf16_dup() avoid assignment in if clause.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 90b6372..770c67a 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -106,7 +106,7 @@
 {
 	size_t len;
 
-	len = utf16_strlen((u16 *)variable_name);
+	len = u16_strlen((u16 *)variable_name);
 	if (len >= MAX_VAR_NAME)
 		return EFI_DEVICE_ERROR;