ARM: dts: ixp4xx: Fix up the Netgear WG302 device tree

ARM: dts: ixp4xx: Fix up the Netgear WG302 device tree

The version we can support (because of access to the hardware)
is WG302v1, so rename the file and make the following
modifications:

- We have 32MB memory not 16MB
- The default console speed is 9600 baud so use this
- The device has no ATA disk nor USB so drop the /dev/sda1
  default mount, this needs to mount ramdisk or NFS
- Both serial0 and serial1 cannot be assigned with aliases,
  just assign serial0
- The Flash is just 8MB so augment the size
- The Flash FIS index is at eraseblock 0x3f
- The PHY is at MDIO address 30

Tested by bringing the Netgear WG302v1 up to userspace using
initramfs appended to the kernel and downloaded over TFTP,
then ifconfig to bring up eth0 and pinging the host. All
works fine including SSH into the device from the host.

Cc: Zoltan HERPAI <wigyori@uid0.hu>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>