In do_abort_rpl_rss, the null check of 'clk' is not needed.

Link: https://lore.kernel.org/r/20200402110832.12712-1-vulab@iscas.ac.cnSigned-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>