arch/s390: clean up hugetlb definitions

arch/s390: clean up hugetlb definitions

s390 redefines functions that are already defined (and the same) in
include/asm-generic/hugetlb.h.

Do as the other architectures:
1) include include/asm-generic/hugetlb.h
2) drop the already defined functions in the generic hugetlb.h and
3) use the __HAVE_ARCH_HUGE_* macros to define our own.

This gets rid of quite some code.

Link: https://lkml.kernel.org/r/20241007075037.267650-9-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>