hwmon: (dell-smm) Warn if SMM call took a very long time to execute

If a particular SMM call takes a very long time to execute,
the user might experience audio problems. Print a warning
if a particular SMM call took over 0.250 seconds to execute,
so the user can check whether or not possible audio problems
are caused by this driver.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20220426213154.724708-4-W_Armin@gmx.de


Signed-off-by: Guenter Roeck <linux@roeck-us.net>