net: fill in MODULE_DESCRIPTION()s for PCS drivers

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the Lynx, XPCS and LynxI PCS drivers.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/pcs/pcs-lynx.c

@@ -398,4 +398,5 @@ void lynx_pcs_destroy(struct phylink_pcs *pcs)
 }
 EXPORT_SYMBOL(lynx_pcs_destroy);
 
+MODULE_DESCRIPTION("NXP Lynx PCS phylink library");
 MODULE_LICENSE("Dual BSD/GPL");

drivers/net/pcs/pcs-mtk-lynxi.c

@@ -303,4 +303,5 @@ void mtk_pcs_lynxi_destroy(struct phylink_pcs *pcs)
 }
 EXPORT_SYMBOL(mtk_pcs_lynxi_destroy);
 
+MODULE_DESCRIPTION("MediaTek SGMII library for LynxI");
 MODULE_LICENSE("GPL");

drivers/net/pcs/pcs-xpcs.c

@@ -1456,4 +1456,5 @@ struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr,
 }
 EXPORT_SYMBOL_GPL(xpcs_create_mdiodev);
 
+MODULE_DESCRIPTION("Synopsys DesignWare XPCS library");
 MODULE_LICENSE("GPL v2");