ARM: dts: msm: switch to RPM control for regulators on MSMFALCON

Convert most of the pmfalcon stub-regulator devices to a
rpm-smd-regulator devices. This ensures that requests made for
these regulators are aggregated by the RPM processor along with
the requests from other processors.
Also, add a dummy gfx_vreg_corner regulator until the CPR node
is added.

While at it, rename all regulators names and add pm/pm2 prefix
to differentiate between regulators on multiple supported PMICs.
Also update all clients with new regulator phandles.

CRs-Fixed: 1077493
Change-Id: I95b17de5bf17b62096d2c9d60633b6b30768752a
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>