socfpga: Adding System Manager driver

Adding System Manager driver which will configure the
pin mux for real hardware Cyclone V development kit
(not Virtual Platform)

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