mm/mglru: improve reset_mm_stats()

mm/mglru: improve reset_mm_stats()

struct lruvec* is already a field of struct lru_gen_mm_walk.  Remove the
parameter struct lruvec* into functions that already have access to struct
lru_gen_mm_walk*.

Also, we do not need to handle reset histogram stats when
!should_walk_mmu().  Remove the call to reset_mm_stats() in
iterate_mm_list_nowalk().

Link: https://lkml.kernel.org/r/20240214060538.3524462-4-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>