constify iov_iter_count() and iter_is_iovec()

BugLink: http://bugs.launchpad.net/bugs/1650607

commit b57332b4 upstream.

[stable note, need this to prevent build warning in commit
a0ac402c]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

include/linux/uio.h

@@ -101,12 +101,12 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages);
 
 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
 
-static inline size_t iov_iter_count(struct iov_iter *i)
+static inline size_t iov_iter_count(const struct iov_iter *i)
 {
 	return i->count;
 }
 
-static inline bool iter_is_iovec(struct iov_iter *i)
+static inline bool iter_is_iovec(const struct iov_iter *i)
 {
 	return !(i->type & (ITER_BVEC | ITER_KVEC));
 }