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

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

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

When we run syzkaller we get below Out of Bound.

"KASAN: slab-out-of-bounds Read in regcache_flat_read"

Below is the backtrace of the issue:

dump_backtrace+0x0/0x4c8

show_stack+0x34/0x44

dump_stack_lvl+0xd8/0x118

print_address_description+0x30/0x2d8

kasan_report+0x158/0x198

__asan_report_load4_noabort+0x44/0x50

regcache_flat_read+0x10c/0x110

regcache_read+0xf4/0x180

_regmap_read+0xc4/0x278

_regmap_update_bits+0x130/0x290

regmap_update_bits_base+0xc0/0x15c

snd_soc_component_update_bits+0xa8/0x22c

snd_soc_component_write_field+0x68/0xd4

tx_macro_digital_mute+0xec/0x140

Actually There is no need to have decimator with 32 bits.

By limiting the variable with short type u8 issue is resolved.