ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

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

ASoC: SOF: ipc4-topology: Fix shift-out-of-bounds for aggregated ALH capture

When ch_count is smaller than blob->alh_cfg.device_count (e.g. a mono
capture stream, such as a SmartMic, aggregated across multiple SDW
links), step = ch_count / blob->alh_cfg.device_count truncates to 0.
The subsequent GENMASK(step - 1, 0) then underflows step - 1 (u32) to
UINT_MAX, causing GENMASK()'s internal shift to use an out-of-bounds
exponent:

UBSAN: shift-out-of-bounds in sound/soc/sof/ipc4-topology.c:2363:13
shift exponent 18446744069414584384 is too large for 64-bit type 'long unsigned int'

Treat ch_count < device_count the same way as the existing "channels
equal to output reference channels" case: apply the same ch_mask to
every aggregated device instead of trying to split channels that
can't be evenly divided.