net/phy: micrel: fix bugged test on device tree loading for ksz9021

In ksz9021_load_values_from_of() val2 to val4 aren't tested against their
initialization value.
This causes the test to always succeed, and this value to be used as if it
was loaded from the devicetree instead of being ignored, in case of a
missing/invalid property in the ethernet OF device node.
As a result, the value "0" is written to the relevant registers.

Change the conditions to test against the right initialization value.

Signed-off-by: Hubert Chaumette <hchaumette@adeneo-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>