powerpc/fsl_soc: gianfar: don't probe disabled devices

Freescale ships MPC8315E-RDB boards in two variants:

1. With TSEC1 ethernet support and USB UTMI PHY;
2. Without TSEC1 support, but with USB ULPI PHY in addition.

For the second case U-Boot will add status = "disabled"; property
into the TSEC1 node, so Linux should not try to probe it.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/sysdev/fsl_soc.c

@@ -296,6 +296,9 @@ static int __init gfar_of_init(void)
 		const phandle *ph;
 		int n_res = 2;
 
+		if (!of_device_is_available(np))
+			continue;
+
 		memset(r, 0, sizeof(r));
 		memset(&gfar_data, 0, sizeof(gfar_data));