checkpatch: warn on uapi #includes that #include <uapi/...

Avoid specifying internal uapi #include paths with uapi/...  as
userspace should not use and never see that.

Neaten message line wrapping above.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -2226,8 +2226,11 @@ sub process {
 			my $path = $1;
 			if ($path =~ m{//}) {
 				ERROR("MALFORMED_INCLUDE",
-				      "malformed #include filename\n" .
-					$herecurr);
+				      "malformed #include filename\n" . $herecurr);
+			}
+			if ($path =~ "^uapi/" && $realfile =~ m@\binclude/uapi/@) {
+				ERROR("UAPI_INCLUDE",
+				      "No #include in ...include/uapi/... should use a uapi/ path prefix\n" . $herecurr);
 			}
 		}