khugepage: replace lru_cache_add() with folio_add_lru()

Replaces some calls with their folio equivalents.  This is in preparation
for the removal of lru_cache_add().  This replaces 3 calls to
compound_head() with 1.

Link: https://lkml.kernel.org/r/20221101175326.13265-5-vishal.moola@gmail.com


Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>