net: phy: mscc-miim: remove redundant timeout check

readl_poll_timeout already returns -ETIMEDOUT if the condition isn't
satisfied, there's no need to check again the condition after calling
it. Remove the redundant timeout check.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>