ARM: socfpga: initial support for Altera's SOCFPGA platform

Adding core definitions for Altera's SOCFPGA ARM platform.
Mininum support for Altera's SOCFPGA Cyclone 5 hardware.

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Reviewed-by: Pavel Machek <pavel@denx.de>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>