regulator: helpers: Ensure bypass register field matches ON value

When checking bypass state for a regulator, we check to see if any bits
in the bypass mask are set. For most cases this is fine because there is
typically, only a single bit used to determine if the regulator is in
bypass. However, for some regulators, such as LDO6 on AS3722, the bypass
state is indicate by a value rather than a single bit. Therefore, when
checking the bypass state, check that the bypass field matches the ON
value.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>