Simplify 32-bit and 64-bit Intel SoCFPGA Kconfig options by having only
one for both of them.  This the common practice for other platforms.
Additionally, the ARCH_SOCFPGA is too generic as SoCFPGA designs come
from multiple vendors.
Signed-off-by: NKrzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: NDinh Nguyen <dinguyen@kernel.org>