clk: imx: Add clock driver for i.MX8MQ CCM

Add driver for the Clock Control Module found on i.MX8MQ.

Signed-off-by: Anson Huang <anson.huang@nxp.com>
Signed-off-by: Bai Ping <ping.bai@nxp.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>