phy: mscc: Use PHY_ID_MATCH_EXACT for VSC8584, VSC8582, VSC8575, VSC856X

phy: mscc: Use PHY_ID_MATCH_EXACT for VSC8584, VSC8582, VSC8575, VSC856X

As the PHYs VSC8584, VSC8582, VSC8575 and VSC856X exists only as rev B,
we can use PHY_ID_MATCH_EXACT to match exactly on revision B of the PHY.
Because of this change then there is not need the check if it is a
different revision than rev B in the function vsc8584_probe() as we
already know that this will never happen.
These changes are a preparation for the next patch because in that patch
we will make the PHYs VSC8574 and VSC8572 to use vsc8584_probe() and
these PHYs have multiple revision.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://patch.msgid.link/20251023191350.190940-2-horatiu.vultur@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>