ASoC: SOF: ipc3-dtrace: fix potential integer overflow in allocation

Fix a potential integer overflow vulnerability in trace_filter_parse()
where the allocation size calculation could overflow.

The issue occurs when:
1. capacity is calculated by adding TRACE_FILTER_ELEMENTS_PER_ENTRY in a
loop for each entry found in the input string.
2. capacity * sizeof(**out) multiplication could overflow if many
entries are present in the input.
3. This results in a smaller allocation than expected, leading to
potential buffer overflow.

Replace kmalloc() with kmalloc_array() which provides built-in overflow
checking and will safely fail the allocation if overflow would occur,
preventing memory corruption.

Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Link: https://patch.msgid.link/20250909225111.3740029-1-samasth.norway.ananda@oracle.com
Signed-off-by: Mark Brown <broonie@kernel.org>