audio: dcblock: reject mismatched source/sink frame formats in prepare

[Copilot]

dcblock_prepare() selected the processing function solely from cd->source_format without verifying the sink format matches. A mismatched pipeline would silently proceed and corrupt output by interpreting the sink buffer with the wrong sample type/width.

Change

• src/audio/dcblock/dcblock.c: Add an explicit format equality check in dcblock_prepare() after both formats are fetched; return -EINVAL if they differ.

if (cd->source_format != cd->sink_format) {
    comp_err(dev, "source and sink frame formats do not match");
    return -EINVAL;
}

This follows the same defensive pattern used for channel-count validation in the same function.

[sofci]

Can one of the admins verify this patch?

reply test this please to run this test once