ARM: ux500: Provide regulator support for SMSC911x via Device Tree

This patch adds a fixed regulator for use by the SMSC911x Ethernet
chip driver into the db8500 Device Tree. It also references other
regulators required by the same device.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>