ASoC: samsung: spdif: Convert to devm_ioremap_resource()

ASoC: samsung: spdif: Convert to devm_ioremap_resource()

Replace the open-coded request_mem_region() + ioremap() sequence with
devm_ioremap_resource(), which handles both the region claim and mapping
under devres lifetime management.

This eliminates the manual iounmap() and release_mem_region() calls in
the error path (err3/err4 labels) and in spdif_remove(), simplifying
the probe error handling.

Signed-off-by: Jihed Chaibi <jihed.chaibi.dev@gmail.com>
Link: https://patch.msgid.link/20260324223907.98897-1-jihed.chaibi.dev@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>