ARM: dts: blanche: add Ethernet pins

Add the (previously omitted) pin data for the SMSC LAN89218 Ethernet chip
to  the Blanche board's device tree:  the chip's IRQ output is connected to
the SoC's IRQ0 pin and its nCS input is connected to the SoC's EX_CS0# pin.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>