Convert qcom pm8941 power key binding from .txt to .yaml format.

The example has been removed in favour of full example being
available in the qcom,pon.yaml binding.
Signed-off-by: satya priya <skakit@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1620800053-26405-5-git-send-email-skakit@codeaurora.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>