devm_kasprintf() can return a NULL pointer on failure but this returned
value is not checked.

Fix this lack and check the returned value.

Fixes: 075c7125 ("ASoC: fsl: Add support for QMC audio")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://patch.msgid.link/20240701113038.55144-2-herve.codina@bootlin.comSigned-off-by: Mark Brown <broonie@kernel.org>