ASoC: SOF: ipc4-topology: Fix a less than zero check on a u32

ASoC: SOF: ipc4-topology: Fix a less than zero check on a u32

Currently the error check from the call to sof_ipc4_get_sample_type
is always false because a u32 variable out_ref_type is being used
to perform the less than zero check. Fix this by using the int
variable ret to perform the check.

Fixes: c04c2e829649 ("ASoC: SOF: ipc4-topology: Add support for 8-bit formats")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://patch.msgid.link/20250902083213.2620124-1-colin.i.king@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>