at86rf230: remove invalid max csma backoffs check

This patch removes the invalid check on max csma backoffs in driver
layer. This is already handled by nl802154 framework.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c
index 05d4f8f..aea00d3 100644
--- a/drivers/net/ieee802154/at86rf230.c
+++ b/drivers/net/ieee802154/at86rf230.c
@@ -1167,9 +1167,6 @@
 	struct at86rf230_local *lp = hw->priv;
 	int rc;
 
-	if (retries > 5)
-		return -EINVAL;
-
 	rc = at86rf230_write_subreg(lp, SR_MIN_BE, min_be);
 	if (rc)
 		return rc;