ASoC: da7218: Fix incorrect usage of bitwise '&' operator for SRM check

In the SRM lock check section of code the '&' bitwise operator is
used as part of checking lock status. Functionally the code works
as intended, but the conditional statement is a boolean comparison
so should really use '&&' logical operator instead. This commit
rectifies this discrepancy.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Mark Brown <broonie@kernel.org>