ASoC: fsl: fsl_audmix: Validate written enum values

In the Linux kernel, the following vulnerability has been resolved: ASoC: fsl: fsl_audmix: Validate written enum values fsl_audmix_put_mix_clk_src() and fsl_audmix_put_out_src() convert the user-provided enum item with snd_soc_enum_item_to_val() before checking whether the item is within the enum's item count. The generic snd_soc_put_enum_double() helper performs that validation, but these callbacks use the converted value first: the clock-source path tests it with BIT(), and the output-source path indexes the prms transition table with it. Reject out-of-range enum items before converting them.