xwayland: Include <sys/type.h> where needed

With the addition of linux_dmabuf v4, the code adds dev_t in various places but did not include <sys/type.h>.

While that works on glibc, it may fail to build on other libc implementations such as musl libc.

Make sure to explicitly include <sys/type.h> where we use dev_t.

Signed-off-by: Olivier Fourdan ofourdan@redhat.com Closes: #1445 (closed) Fixes: bddfe190 - Implement linux_dmabuf_feedback event handlers