ASoC: uniphier: Simplify the return expression of uniphier_aio_startup

Simplify the return expression in the aio-cpu.c.

Signed-off-by: dingsenjie <dingsenjie@yulong.com>
Link: https://lore.kernel.org/r/20210224085407.22120-1-dingsenjie@163.com


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