mm/oom_killer: simplify OOM killer info dump helper

mm/oom_killer: simplify OOM killer info dump helper

There is only one caller wants to dump the kill victim info, so just let
it call the standalone helper, no need to make the generic info dump
helper take an extra argument for that.

Result of bloat-o-meter:
./scripts/bloat-o-meter ./mm/oom_kill.old.o ./mm/oom_kill.o
add/remove: 0/0 grow/shrink: 1/2 up/down: 131/-142 (-11)
Function                                     old     new   delta
oom_kill_process                             412     543    +131
out_of_memory                               1422    1418      -4
dump_header                                  562     424    -138
Total: Before=21514, After=21503, chg -0.05%

Link: https://lkml.kernel.org/r/20231016113103.86477-1-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>