ASoC: soc-ops: cleanup cppcheck warning at snd_soc_get_xr_sx()

This patch cleanups below cppcheck warning.

sound/soc/soc-ops.c:814:15: style: The scope of the variable 'regval' can be reduced. [variableScope]
 unsigned int regval;
              ^

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/871r7bw29k.wl-kuninori.morimoto.gx@renesas.com


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