ASoC: SMA1303: set sma_i2c_regmap storage-class-specifier to static

smatch reports
sound/soc/codecs/sma1303.c:1594:28:
  warning: symbol 'sma_i2c_regmap' was not declared. Should it be static?

sma_i2c_regmap is only used in sma1303, so it should be static

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230309140959.2616497-1-trix@redhat.com


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