kernel: modules: fix mdio-bus-mux description

Simple error during copy/paste

Fixes: 2dbeb607251b ("kernel: add mdio-bus-mux support")
Signed-off-by: Luiz Angelo Daros de Luca <[email protected]>

package/kernel/linux/modules/netsupport.mk

@@ -1372,7 +1372,7 @@ define KernelPackage/mdio-bus-mux
   AUTOLOAD:=$(call AutoLoad,32,mdio-mux)
 endef
 
-define KernelPackage/mdio/description
+define KernelPackage/mdio-bus-mux/description
  Kernel framework for MDIO bus multiplexers.
 endef