clk: hisilicon: Delete an error message for a failed memory allocation in hisi_register_clkgate_sep()

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>