coccinelle: api: extend memdup_user transformation with GFP_USER

Match GFP_USER and optional __GFP_NOWARN allocations with
memdup_user.cocci rule.
Commit 6c2c97a ("memdup_user(): switch to GFP_USER") switched
memdup_user() from GFP_KERNEL to GFP_USER. In almost all cases it
is still a good idea to recommend memdup_user() for GFP_KERNEL
allocations. The motivation behind altering memdup_user() to GFP_USER:
https://lkml.org/lkml/2018/1/6/333

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

Author: evdenis

scripts/coccinelle/api/memdup_user.cocci

@@ -20,7 +20,9 @@ expression from,to,size;
 identifier l1,l2;
 @@
 
--  to = \(kmalloc\|kzalloc\)(size,GFP_KERNEL);
+-  to = \(kmalloc\|kzalloc\)
+-		(size,\(GFP_KERNEL\|GFP_USER\|
+-		      \(GFP_KERNEL\|GFP_USER\)|__GFP_NOWARN\));
 +  to = memdup_user(from,size);
    if (
 -      to==NULL
@@ -43,7 +45,9 @@ position p;
 statement S1,S2;
 @@
 
-*  to = \(kmalloc@p\|kzalloc@p\)(size,GFP_KERNEL);
+*  to = \(kmalloc@p\|kzalloc@p\)
+		(size,\(GFP_KERNEL\|GFP_USER\|
+		      \(GFP_KERNEL\|GFP_USER\)|__GFP_NOWARN\));
    if (to==NULL || ...) S1
    if (copy_from_user(to, from, size) != 0)
    S2