wolfSSL: Fix the memory leak of crypto_ec_point_compute_y_sqr()

Local variable "t" needs to be cleared whether "calced" is 0 or 1.

Signed-off-by: 赵军涛 <d2014zjt@163.com>

src/crypto/crypto_wolfssl.c

@@ -1678,9 +1678,9 @@ done:
 			mp_clear(y2);
 			os_free(y2);
 		}
-		mp_clear(&t);
 	}
 
+	mp_clear(&t);
 	return (struct crypto_bignum *) y2;
 }