net: dm: fec: Fix phy-reset-duration clamping and defaults

net: dm: fec: Fix phy-reset-duration clamping and defaults

The DT binding says:
- phy-reset-duration : Reset duration in milliseconds.  Should present
  only if property "phy-reset-gpios" is available.  Missing the property
  will have the duration be 1 millisecond.  Numbers greater than 1000 are
  invalid and 1 millisecond will be used instead.

However the current code:
 - clamps values greater than 1000ms to 1000ms rather than 1.
 - does not initialize the delay if the property does not exist
   (else clause mismatch)
 - returns an error if phy-reset-gpios is not defined

Fix all this and simplify by using dev_read_u32_default()

Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>