checkpatch: add __pmem to $Sparse annotations

commit 61031952 ("arch, x86: pmem api for ensuring durability of
persistent memory updates") added a new __pmem annotation for sparse
verification.  Add __pmem to the $Sparse variable so checkpatch can
appropriately ignore uses of this attribute too.
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.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

@@ -264,6 +264,7 @@ our $Sparse	= qr{
 			__kernel|
 			__force|
 			__iomem|
+			__pmem|
 			__must_check|
 			__init_refok|
 			__kprobes|