regulator: qcom_rpm: Fix FORCE_MODE_IS_2_BITS macro

Current code does not take the macro parameter, fix it.
This is not a problem at this moment because the only user actually passes
vreg to FORCE_MODE_IS_2_BITS().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>