arm/dt: msm8974: Remove qcom,allow-atomic regulator properties

Clock and acpuclock drivers no longer require atomic access for
regulators.  Thus, remove device tree configuration properties on
regulators pm8841_s2, pm8941_s2, and pm8941_l12 which allow for
atomic access.

This change will remove latency which is present when holding a
spinlock while waiting for the RPM to acknowledge a regulator
request.

Change-Id: I1e3a299244471515079b7a04d64a0147c0a509e4
Signed-off-by: David Collins <collinsd@codeaurora.org>