ASoC: sdw_utils: Check speaker component string allocation

ASoC: sdw_utils: Check speaker component string allocation

devm_kasprintf() can fail while building the temporary speaker
component string. If that happens, spk_components is set to NULL, but
the current code can still pass it to strlen() on a later loop iteration
or after the loop when appending the speaker component list to
card->components.

Use NULL to represent the initial "no speaker components" state, and
return -ENOMEM immediately if building spk_components fails.

Fixes: 0f60ecffbfe3 ("ASoC: sdw_utils: generate combined spk components string")
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260512-asoc-sdw-utils-spk-components-alloc-v1-1-c9bbd6d2e123@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>