ASoC: soc-dai: cleanup cppcheck warning at snd_soc_dai_link_set_capabilities()

ASoC: soc-dai: cleanup cppcheck warning at snd_soc_dai_link_set_capabilities()

This patch cleanups below cppcheck warning.

sound/soc/soc-dai.c:454:7: style: The scope of the variable 'supported_cpu' can be reduced. [variableScope]
 bool supported_cpu;
      ^
sound/soc/soc-dai.c:455:7: style: The scope of the variable 'supported_codec' can be reduced. [variableScope]
 bool supported_codec;
      ^

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87y292yom6.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>