ARM: shmobile: r8a7778: fix Ether device name

While recasting commit 52421914 (ARM: shmobile:
R8A7778: add Ether support), I made a typo in the platform device's name: used
underscore instead of hyphen.

However, there's now patch merged to net-next.git renaming the platform device
from "sh-eth" to "r8a777x-ehter", so it makes the most sense to change the name
straight to that one.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/setup-r8a7778.c

@@ -96,7 +96,7 @@ static struct resource ether_resources[] = {
 
 void __init r8a7778_add_ether_device(struct sh_eth_plat_data *pdata)
 {
-	platform_device_register_resndata(&platform_bus, "sh_eth", -1,
+	platform_device_register_resndata(&platform_bus, "r8a777x-ether", -1,
 					  ether_resources,
 					  ARRAY_SIZE(ether_resources),
 					  pdata, sizeof(*pdata));