Revert "mm/page_alloc: make should_fail_alloc_page() static"

Revert "mm/page_alloc: make should_fail_alloc_page() static"

This reverts commit f7173090033c70886d925995e9dfdfb76dbb2441.

Fix an unresolved symbol error when CONFIG_DEBUG_INFO_BTF=y:

    LD      vmlinux
    BTFIDS  vmlinux
  FAILED unresolved symbol should_fail_alloc_page
  make: *** [Makefile:1199: vmlinux] Error 255
  make: *** Deleting file 'vmlinux'

Link: https://lkml.kernel.org/r/[email protected]
Fixes: f7173090033c ("mm/page_alloc: make should_fail_alloc_page() static")
Signed-off-by: Matteo Croce <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Tested-by: John Hubbard <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>