mfd: macsmc: Initialize mutex

[Lee Jones]

On Wed, 01 Oct 2025, Markus Elfring wrote:

> >>>>> Struct apple_smc's mutex was not initialized before use. Surprisingly
> >>>>> this only resulted in occasional NULL pointer dereferences in
> >>>>> apple_smc_read() calls from the probe() functions of sub devices.
> …> However, you must also provide your own context.
> 
> Do you try to support the creation of improved change descriptions?

Not to -pedantic levels, no.

-- 
Lee Jones [李琼斯]