ARM: imx6q: prepare and enable init on clks directly instead of clk_get first

This also removes the usboh3 clk from the initially turned on
clocks which leaked in from an internal development tree.

Signed-off-by: Richard Zhao <richard.zhao@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>