dt-bindings: add i.mx6ul clock header

Add i.mx6ul clock header, copied from kernel commit (29b4817d401).
i.MX6ULL reuse the file in Linux Kernel, so let's keep the same.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>
1 file changed