[PATCH] mfd: macsmc: Initialize mutex

[Markus Elfring]

> 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.

See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.17-rc7#n94

Regards,
Markus