[ARM] add coherent DMA mask for mv643xx_eth

Since commit eb0519b5a1cf, mv643xx_eth is non functional on ARM because
the platform device declaration does not include any coherent DMA mask
and coherent memory allocations fail.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
diff --git a/arch/arm/mach-kirkwood/common.c b/arch/arm/mach-kirkwood/common.c
index 3fab82a..be1ca28 100644
--- a/arch/arm/mach-kirkwood/common.c
+++ b/arch/arm/mach-kirkwood/common.c
@@ -144,6 +144,9 @@
 	.id		= 0,
 	.num_resources	= 1,
 	.resource	= kirkwood_ge00_resources,
+	.dev		= {
+		.coherent_dma_mask	= 0xffffffff,
+	},
 };
 
 void __init kirkwood_ge00_init(struct mv643xx_eth_platform_data *eth_data)
@@ -202,6 +205,9 @@
 	.id		= 1,
 	.num_resources	= 1,
 	.resource	= kirkwood_ge01_resources,
+	.dev		= {
+		.coherent_dma_mask	= 0xffffffff,
+	},
 };
 
 void __init kirkwood_ge01_init(struct mv643xx_eth_platform_data *eth_data)