ARM: dts: omap3-beagle: Use reset-gpios for hsusb2_reset

We no longer need to model the RESET line as a regulator since
the USB phy-nop driver accepts "reset-gpios" property.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Benoit Cousson <bcousson@baylibre.com>