ARM: dts: Set Peach boards USB WebCam regulators to always on

The Exynos5420 Peach Pit and Exynos5800 Peach Pi boards have a built-in
Silicon Motion USB UVC WebCam whose power supply is the tps65090 fet5
regulator. Since the camera uses the generic USB Video Class driver and
this does not grab a regulator, mark the regulator as always on so the
USB device is enumerated and usable.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>