ASoC: amd: pcm-dma: Fix signedness bug in acp_pdm_audio_probe()

The "adata->pdm_irq" variable is unsigned so the error handling will
not work.

Fixes: 87d71a12 ("ASoC: amd: pcm-dma: Use platform_get_irq() to get the interrupt")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220304131335.GB28739@kili


Signed-off-by: Mark Brown <broonie@kernel.org>