CVE-2026-74294: ASoC: meson: aiu: Validate written enum values

In the Linux kernel, the following vulnerability has been resolved:

ASoC: meson: aiu: Validate written enum values

The AIU HDMI and internal codec mux put callbacks use the written enum value with sndsocenumitemtoval() before checking whether the value is valid for the enumeration.

Reject out-of-range values before converting the enum item, matching the validation already done by the G12A HDMI and internal codec mux controls.