net: phy: mscc: Consolidate probe functions into a common helper

net: phy: mscc: Consolidate probe functions into a common helper

Unify the probe implementations of the VSC85xx PHY family into a single
vsc85xx_probe_common() helper. The existing probe functions for the
vsc85xx, vsc8514, vsc8574, and vsc8584 variants contained almost
identical initialization logic, differing only in configuration
parameters such as the number of LEDs, supported LED modes, hardware
statistics, and PTP support.

Introduce a vsc85xx_probe_config structure to describe the per-variant
parameters, and move all common setup code into the shared helper. Each
variant's probe function now defines a constant configuration instance
and calls vsc85xx_probe_common().

Also mark the default LED mode array parameter as const to match its
usage.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20251112135715.1017117-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>