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

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

This patch cleanups below cppcheck warning.

sound/soc/soc-dapm.c:653:20: style: The scope of the variable 'wlist' can be reduced. [variableScope]
 struct list_head *wlist;
                   ^
sound/soc/soc-dapm.c:655:6: style: The scope of the variable 'i' can be reduced. [variableScope]
 int i = 0;
     ^

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87y29gu25d.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>