kernel/crash_core.c: remove redundant check of ck_cmdline

kernel/crash_core.c: remove redundant check of ck_cmdline

At the end of get_last_crashkernel(), the judgement of ck_cmdline is
obviously unnecessary and causes redundance, let's clean it up.

Link: https://lkml.kernel.org/r/20220506104116.259323-1-sensor1010@163.com
Signed-off-by: lizhe <sensor1010@163.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Philipp Rudo <prudo@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>