microchip: lan865x: add ndo_eth_ioctl handler to enable PHY ioctl support

microchip: lan865x: add ndo_eth_ioctl handler to enable PHY ioctl support

Introduce support for standard MII ioctl operations in the LAN865x
Ethernet driver by implementing the .ndo_eth_ioctl callback. This allows
PHY-related ioctl commands to be handled via phy_do_ioctl_running() and
enables support for ethtool and other user-space tools that rely on ioctl
interface to perform PHY register access using commands like SIOCGMIIREG
and SIOCSMIIREG.

This feature enables improved diagnostics and PHY configuration
capabilities from userspace.

Signed-off-by: Parthiban Veerasooran <parthiban.veerasooran@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250828114549.46116-1-parthiban.veerasooran@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>