clk: socfpga: arria10: Fix memory leak of socfpga_clk on error return

There is an error return path that is not kfree'ing socfpga_clk leading
to a memory leak. Fix this by adding in the missing kfree call.

Addresses-Coverity: ("Resource leak")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210406170115.430990-1-colin.king@canonical.com
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>