socfpga: Adding Clock Manager driver

Clock Manager driver will be called to reconfigure all the
clocks setting based on user input. The input are passed to
Preloader through handoff files

Signed-off-by: Chin Liang See <clsee@altera.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Tom Rini <trini@ti.com>
Cc: Wolfgang Denk <wd@denx.de>
CC: Pavel Machek <pavel@denx.de>
Cc: Dinh Nguyen <dinguyen@altera.com>
Acked-by: Pavel Machek <pavel@denx.de>