microchip: lan865x: Fix module autoloading

microchip: lan865x: Fix module autoloading

Add MODULE_DEVICE_TABLE(), so modules could be properly autoloaded
based on the alias from spi_device_id table. While at this, fix
the misleading variable name (spidev is unrelated to this driver).

Fixes: 5cd2340cb6a3 ("microchip: lan865x: add driver support for Microchip's LAN865X MAC-PHY")
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Cc: stable@kernel.org
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250827115341.34608-3-wahrenst@gmx.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>