ASoC: Use __counted_by() annotation for snd_soc_pcm_runtime

ASoC: Use __counted_by() annotation for snd_soc_pcm_runtime

The struct snd_soc_pcm_runtime has a flex array of snd_soc_component
objects at its end, and the size is kept in num_components field.
We can add __counted_by() annotation for compiler's assistance to
catch array overflows.

A slight additional change is the assignment of rtd->components[];
the array counter has to be incremented at first for avoiding
false-positive reports from compilers.

Also, the allocation size of snd_soc_pcm_runtime is cleaned up with
the standard struct_size() helper, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20240726155237.21961-1-tiwai@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>