net: phy: adin: fix a warning about msleep

found a warning by the following command:
./scripts/checkpatch.pl -f drivers/net/phy/adin.c

WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.rst
#628: FILE: drivers/net/phy/adin.c:628:
+ msleep(10);

Signed-off-by: Dejin Zheng <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/adin.c

···
 	if (rc < 0)
 		return rc;
 
-	msleep(10);
+	msleep(20);
 
 	/* If we get a read error something may be wrong */
 	rc = phy_read_mmd(phydev, MDIO_MMD_VEND1,