mfd: omap-usb-host: Use proper clock name instead of alias

Use the proper clock name 'usbhost_120m_fck' instead of the
alias 'ehci_logic_fck'

Get rid of the 'ehci_logic_fck' alias from the OMAP3 hwmod data
as well.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>