ASoC: rsnd: add regmap_config::name for debugfs

Renesas sound driver needs SSI/SRC/DVC regmaps, but it didn't have
regmap_config::name for devm_regmap_init_mmio().
Thus, debugfs initialization code tried to use same driver name
many times, and failed.
This patch adds eacy own name for regmap_config::name

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>