rpm-smd: Fix rpm-smd-regulator probe deferral issue

The of_platform_populate of rpm-smd-regulator gets called before
probe_status is set. Fix the probe_status before the function call.

Change-Id: Ie614e856852c6f5b7403af26b06b46d1c4738ff8
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>