tools: mkeficapsule: remove duplicated code

That code is mistakenly duplicated due to copy-and-paste error.
Just remove it.

Fixes: CID 348360
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

tools/mkeficapsule.c

@@ -210,8 +210,6 @@ static int create_auth_data(struct auth_context *ctx)
 	cert.size = file_size;
 
 	ret = read_bin_file(ctx->key_file, &key.data, &file_size);
-	if (ret < 0)
-		return -1;
 	if (ret < 0)
 		return -1;
 	if (file_size > UINT_MAX)