clk: socfpga: allow compile testing of Stratix 10 / Agilex clocks

clk: socfpga: allow compile testing of Stratix 10 / Agilex clocks

The Stratix 10 / Agilex / N5X clocks do not use anything other than OF
or COMMON_CLK so they should be compile testable on most of the
platforms.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>