mm, gfp: escalatedly define GFP_HIGHUSER and GFP_HIGHUSER_MOVABLE

mm, gfp: escalatedly define GFP_HIGHUSER and GFP_HIGHUSER_MOVABLE

GFP_USER, GFP_HIGHUSER and GFP_HIGHUSER_MOVABLE are escalatedly confined
defined, also implied by their names:

GFP_USER                                  = GFP_USER
GFP_USER + __GFP_HIGHMEM                  = GFP_HIGHUSER
GFP_USER + __GFP_HIGHMEM + __GFP_MOVABLE  = GFP_HIGHUSER_MOVABLE

So just make GFP_HIGHUSER and GFP_HIGHUSER_MOVABLE escalatedly defined to
reflect this fact.  It also makes the definition clear and texturally warn
on any furture break-up of this escalated relastionship.

Signed-off-by: Jianyu Zhan <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>