net/macb: bindings doc/trivial: fix documentation for sama5d3 10/100 interface

This removes a line left while adding the correct compatibility string for
sama5d3 10/100 interface. Now use the "atmel,sama5d3-macb" string.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>