net: aquantia: Fix a regression with reset on old firmware

FW 1.5.58 and below needs a fixed delay even after 0x18 register
is filled. Otherwise, setting MPI_INIT state too fast causes
traffic hang.
Signed-off-by: NIgor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_utils.c

@@ -147,6 +147,8 @@ static int hw_atl_utils_soft_reset_flb(struct aq_hw_s *self)
 		aq_pr_err("FW kickstart failed\n");
 		return -EIO;
 	}
+	/* Old FW requires fixed delay after init */
+	AQ_HW_SLEEP(15);
 
 	return 0;
 }
@@ -214,6 +216,8 @@ static int hw_atl_utils_soft_reset_rbl(struct aq_hw_s *self)
 		aq_pr_err("FW kickstart failed\n");
 		return -EIO;
 	}
+	/* Old FW requires fixed delay after init */
+	AQ_HW_SLEEP(15);
 
 	return 0;
 }