net: phy: micrel: improve HW timestamping config logic

net: phy: micrel: improve HW timestamping config logic

The driver was adjusting stored values independently of what was
actually supported and configured. Improve logic to store values
once all checks are passing

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20260106160723.3925872-2-vadim.fedorenko@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>