The necessary clock phandle for the EHCI clock is now provided
via device tree so we no longer need this legacy method.

Update the omap4-panda and omap5-uevm board DTS to provide the
necessary EHCI PHY clock information.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>