net: fill in MODULE_DESCRIPTION()s for fsl_pq_mdio

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Freescale PQ MDIO driver.
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240123190332.677489-9-leitao@debian.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fsl_pq_mdio.c

@@ -531,4 +531,5 @@ static struct platform_driver fsl_pq_mdio_driver = {
 
 module_platform_driver(fsl_pq_mdio_driver);
 
+MODULE_DESCRIPTION("Freescale PQ MDIO helpers");
 MODULE_LICENSE("GPL");