mm: drop __nocast from vm_flags_t definition

__nocast does no good for vm_flags_t. It only produces useless sparse
warnings.

Let's drop it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm_types.h

@@ -235,7 +235,7 @@ struct page_frag_cache {
 	bool pfmemalloc;
 };
 
-typedef unsigned long __nocast vm_flags_t;
+typedef unsigned long vm_flags_t;
 
 /*
  * A region containing a mapping of a non-memory backed file under NOMMU