The hdmi interface driver exposes functions to the hdmi panel driver to
configure the interface timings maintained by the hdmi driver.

These timings(stored in hdmi.ip_data.cfg) should be protected by the hdmi lock
to ensure they are called sequentially, this is similar to how hdmi enable and
disable functions need locking.
Signed-off-by: Archit Taneja <archit@ti.com>