eficonfig: use u16_strsize() to get u16 string buffer size

Use u16_strsize() to simplify the u16 string buffer
size calculation.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/cmd/eficonfig.c b/cmd/eficonfig.c
index 5529edc..88d507d 100644
--- a/cmd/eficonfig.c
+++ b/cmd/eficonfig.c
@@ -452,8 +452,7 @@
 	struct efi_device_path *dp;
 	struct efi_device_path_file_path *fp;
 
-	fp_size = sizeof(struct efi_device_path) +
-		  ((u16_strlen(current_path) + 1) * sizeof(u16));
+	fp_size = sizeof(struct efi_device_path) + u16_strsize(current_path);
 	buf = calloc(1, fp_size + sizeof(END));
 	if (!buf)
 		return NULL;