ath79: improve TP-Link CPE DTSI names for ar9344 SOC
The initial DTSI names for the TP-Link CPE devices have become
quite confusing, as several non-V1 devices now use the *-v1.dtsi,
the *cpe510-v1.dts does not use the cpe510.dtsi, etc.
This introduces a new naming scheme based on whether devices have
one or two ports, which should be easier to grasp.
Signed-off-by: Adrian Schmutzler <[email protected]>