ASoC: soc-dapm: cleanup cppcheck warning at dapm_set_mixer_path_status()

This patch cleanups below cppcheck warning, and its related code.

 unsigned int val;
              ^

sound/soc/soc-dapm.c:789:15: style: The scope of the variable 'val' can be reduced. [variableScope]
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87v94ku252.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>