espressif: i2c: initialize "has_lock"

Otherwise, a stack-constructed i2c instance might get some other value
here.

ports/espressif/common-hal/busio/I2C.c

@@ -82,6 +82,7 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
     self->sda_pin = sda;
     self->scl_pin = scl;
     self->i2c_num = peripherals_i2c_get_free_num();
+    self->has_lock = 0;
 
     if (self->i2c_num == I2C_NUM_MAX) {
         mp_raise_ValueError(translate("All I2C peripherals are in use"));