mm: kill is_dev_zone() helper

Given there are no more usages of is_dev_zone() outside of 'ifdef
CONFIG_ZONE_DEVICE' protection, kill off the compilation helper.

Signed-off-by: Dan Williams <>
Reviewed-by: Oscar Salvador <>
Reviewed-by: Pavel Tatashin <>
Reviewed-by: Wei Yang <>
Acked-by: David Hildenbrand <>
Tested-by: Aneesh Kumar K.V <>	[ppc64]
Cc: Michal Hocko <>
Cc: Logan Gunthorpe <>
Cc: Jane Chu <>
Cc: Jeff Moyer <>
Cc: Jérôme Glisse <>
Cc: Jonathan Corbet <>
Cc: Mike Rapoport <>
Cc: Toshi Kani <>
Cc: Vlastimil Babka <>
Cc: Jason Gunthorpe <>
Cc: Christoph Hellwig <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
2 files changed