powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section

Move a few kfence and debug_pagealloc related functions in hash_utils.c
and radix_pgtable.c to __init sections since these are only invoked once
by an __init function during system initialization.

i.e.
- hash_debug_pagealloc_alloc_slots()
- hash_kfence_alloc_pool()
- hash_kfence_map_pool()
  The above 3 functions only gets called by __init htab_initialize().

- alloc_kfence_pool()
- map_kfence_pool()
  The above 2 functions only gets called by __init radix_init_pgtable()

This should also help fix warning msgs like:

>> WARNING: modpost: vmlinux: section mismatch in reference:
hash_debug_pagealloc_alloc_slots+0xb0 (section: .text) ->
memblock_alloc_try_nid (section: .init.text)

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504190552.mnFGs5sj-lkp@intel.com/
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20250717232519.2984886-8-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

Author: riteshharjani

arch/powerpc/mm/book3s64/hash_utils.c

@@ -343,7 +343,7 @@ static inline bool hash_supports_debug_pagealloc(void)
 static u8 *linear_map_hash_slots;
 static unsigned long linear_map_hash_count;
 static DEFINE_RAW_SPINLOCK(linear_map_hash_lock);
-static void hash_debug_pagealloc_alloc_slots(void)
+static __init void hash_debug_pagealloc_alloc_slots(void)
 {
 	if (!hash_supports_debug_pagealloc())
 		return;
@@ -409,7 +409,7 @@ static DEFINE_RAW_SPINLOCK(linear_map_kf_hash_lock);
 
 static phys_addr_t kfence_pool;
 
-static inline void hash_kfence_alloc_pool(void)
+static __init void hash_kfence_alloc_pool(void)
 {
 	if (!kfence_early_init_enabled())
 		goto err;
@@ -445,7 +445,7 @@ static inline void hash_kfence_alloc_pool(void)
 	disable_kfence();
 }
 
-static inline void hash_kfence_map_pool(void)
+static __init void hash_kfence_map_pool(void)
 {
 	unsigned long kfence_pool_start, kfence_pool_end;
 	unsigned long prot = pgprot_val(PAGE_KERNEL);

arch/powerpc/mm/book3s64/radix_pgtable.c

@@ -363,7 +363,7 @@ static int __meminit create_physical_mapping(unsigned long start,
 }
 
 #ifdef CONFIG_KFENCE
-static inline phys_addr_t alloc_kfence_pool(void)
+static __init phys_addr_t alloc_kfence_pool(void)
 {
 	phys_addr_t kfence_pool;
 
@@ -393,7 +393,7 @@ static inline phys_addr_t alloc_kfence_pool(void)
 	return 0;
 }
 
-static inline void map_kfence_pool(phys_addr_t kfence_pool)
+static __init void map_kfence_pool(phys_addr_t kfence_pool)
 {
 	if (!kfence_pool)
 		return;