revert "mm/filemap: add static for function __add_to_page_cache_locked"

Revert commit 3351b16 ("mm/filemap: add static for function
__add_to_page_cache_locked") due to incompatibility with
ALLOW_ERROR_INJECTION which result in build errors.

Link: https://lkml.kernel.org/r/CAADnVQJ6tmzBXvtroBuEH6QA0H+q7yaSKxrVvVxhqr3KBZdEXg@mail.gmail.com
Tested-by: Justin Forbes <jmforbes@linuxtx.org>
Tested-by: Greg Thelen <gthelen@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Michal Kubecek <mkubecek@suse.cz>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Tony Luck <tony.luck@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/filemap.c

@@ -827,7 +827,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 }
 EXPORT_SYMBOL_GPL(replace_page_cache_page);
 
-static noinline int __add_to_page_cache_locked(struct page *page,
+noinline int __add_to_page_cache_locked(struct page *page,
 					struct address_space *mapping,
 					pgoff_t offset, gfp_t gfp,
 					void **shadowp)