clk: Emit a stern warning with writable debugfs enabled

clk: Emit a stern warning with writable debugfs enabled

commit 489a71964f9d74e697a12cd0ace20ed829eb1f93 upstream.

We don't want vendors to be enabling this part of the clk code and
shipping it to customers. Exposing the ability to change clk frequencies
and parents via debugfs is potentially damaging to the system if folks
don't know what they're doing. Emit a strong warning so that the message
is clear: don't enable this outside of development systems.

Fixes: 37215da5553e ("clk: Add support for setting clk_rate via debugfs")
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211210014237.2130300-1-sboyd@kernel.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>