NEWEMAC: Add compatible "ibm,tah" to tah matching table

Add "ibm,tah" to the compatible matching table of the ibm_newemac
tah driver. The type "tah" is still preserved for compatibility reasons.
New dts files should use the compatible property though.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>