socfpga: Creating driver for Reset Manager

Consolidating reset code into reset_manager.c. Also
separating reset configuration for virtual target and
real hardware Cyclone V development kit

Signed-off-by: Chin Liang See <clsee@altera.com>
Reviewed-by: Pavel Machek <pavel@denx.de>
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>