Several small fixes for ar8216 driver (patch by Jonas Gorski)

Several small fixes for ar8216 driver (patch by Jonas Gorski)

 * Create defines for some magic values/masks.

 * Change vlan_id to u16, to allow VIDs > 255.

 * Add a range check to set_pvid as it isn't a VID, but the index
   in the vlan table.

 * Set the max VID to 4094, since 4095 is a reserved value and
   should not be used.

 * In mangle_rx replace the provided VID with the VID of the table
   entry of the port, not the index of the table.

 * In hw_apply, remove a redundant emptyness check (was already
   checked several lines above).

 * In no vlan mode do not set the ingress mode to secure, as there
   are no vlan table entries, but to use the port's destination
   masks. Otherwise the switch won't forward anything.

 * In read_status tell that the phy is up (taken from the rtl8306
   driver).

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@20083 3c298f89-4303-0410-b956-a3cf2f4a3e73