ASOC: tpa6130a2: add static qualifier for file local symbols

ASOC: tpa6130a2: add static qualifier for file local symbols

Sparse reports a below warning.

tpa6130a2.c:193:33: warning: symbol 'tpa6130a2_component_driver' was not declared. Should it be static?

The symbol is just used inner the file. Forthermore, it's constant. Thus,
it's better to add static and const qualifier.

This commit adds it.

Fixes: 99dd5280fa1c (ASoC: tpa6130a2: Register component)
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Mark Brown <broonie@kernel.org>