at86rf230: remove check if AVDD settled

The AVDD regulator is only enabled when the RF section is active TX_ON
(PLL_ON) state. Since commit 7dcbd22a97
("ieee802154: ensure that first RF212 state comes from TRX_OFF").
We are in TRX_OFF state at the time at86rf230_hw_init is run.

Note that this test would only fail in case of a severe hardware
malfunction (faulty/shorted power supply, etc.) so it wasn't all that
useful in the first place.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reviewed-by: Werner Almesberger <werner@almesberger.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ieee802154/at86rf230.c

@@ -1025,14 +1025,6 @@ static int at86rf230_hw_init(struct at86rf230_local *lp)
 		return -EINVAL;
 	}
 
-	rc = at86rf230_read_subreg(lp, SR_AVDD_OK, &status);
-	if (rc)
-		return rc;
-	if (!status) {
-		dev_err(&lp->spi->dev, "AVDD error\n");
-		return -EINVAL;
-	}
-
 	return 0;
 }