Linux: Replace lru_cache_add with folio_add_lru

Linux: Replace lru_cache_add with folio_add_lru

The Linux 6.2 commit:
    "folio-compat: remove lru_cache_add()" (6e1ca48d0)
removed the lru_cache_add() function (which was introduced in Linux 5.8)

The replacement function is folio_add_lru(), which was introduced with
the Linux 5.16 commit:
    "mm/lru: Add folio_add_lru()" (0d31125d2d)

Change-Id: I4615e6bde0253618c13ec1eb067e23b2c3e3ff42
Reviewed-on: https://gerrit.openafs.org/15227
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: Benjamin Kaduk <kaduk@mit.edu>