ASoC: cs35l56: Move DSP part string generation so that it is done only once

Each time we go through dsp_work() it does a devm_kasprintf() to
allocate memory to hold the part name string. It's not strictly a memory
leak because devm will free it all if the driver is removed. But we keep
allocating more and more memory to hold the same string.

Move the allocation so that it is performed after the version and
secured state information is gathered and handle allocation errors.

Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/Message-Id

: <20230518150250.1121006-2-rf@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>