kernel: ASoC: codecs: tx-macro: Fix for KASAN: slab-out-of-bounds

A slab-out-of-bounds read vulnerability was found in the Linux kernel's ASoC tx-macro codec driver. The decimator variable was incorrectly sized at 32 bits, causing regcacheflatread to access memory beyond the allocated slab when reading register cache values during the txmacrodigitalmute...