drm/vc4: hdmi: Make sure the device is powered with CEC

Commit 20b0dfa8 upstream.

The original commit depended on a rework commit (724fc856

 ("drm/vc4:
hdmi: Split the CEC disable / enable functions in two")) that
(rightfully) didn't reach stable.

However, probably because the context changed, when the patch was
applied to stable the pm_runtime_put called got moved to the end of the
vc4_hdmi_cec_adap_enable function (that would have become
vc4_hdmi_cec_disable with the rework) to vc4_hdmi_cec_init.

This means that at probe time, we now drop our reference to the clocks
and power domains and thus end up with a CPU hang when the CPU tries to
access registers.

The call to pm_runtime_resume_and_get() is also problematic since the
.adap_enable CEC hook is called both to enable and to disable the
controller. That means that we'll now call pm_runtime_resume_and_get()
at disable time as well, messing with the reference counting.

The behaviour we should have though would be to have
pm_runtime_resume_and_get() called when the CEC controller is enabled,
and pm_runtime_put when it's disabled.

We need to move things around a bit to behave that way, but it aligns
stable with upstream.

Cc: <stable@vger.kernel.org> # 5.10.x
Cc: <stable@vger.kernel.org> # 5.15.x
Cc: <stable@vger.kernel.org> # 5.16.x
Reported-by: Michael Stapelberg <michael+drm@stapelberg.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>