Merge branch 'mailbox-linux-4.1.y' of git://git.ti.com/rpmsg/mailbox into rproc-linux-4.1.y

Pull in the updated mailbox feature branch into the remoteproc
tree for adding mailboxes to the PRU-ICSS PRU cores on AM572x
and AM571x IDKs.

The merge also brings in the up-to-date platform tree with
support for OPP_HIGH support on IVA and DSP DPLLs.

* 'mailbox-linux-4.1.y' of git://git.ti.com/rpmsg/mailbox

:
  ARM: dts: am57xx-idk-common: Enable the system mailboxes 3 and 4
  ARM: dts: DRA72x: Add sub-mailbox nodes for all PRUSS1 & PRUSS2
  ARM: dts: k2g: Remove voltage-ranges property from MMC nodes
  HACK: ARM: dts: am571x-idk: Configure DSP & IVA clocks for OPP_HIGH
  HACK: ARM: dts: am572x-idk: Configure DSP & IVA clocks for OPP_HIGH
  HACK: ARM: dts: am57xx-beagle-x15: Configure DSP & IVA clocks for OPP_HIGH
  HACK: ARM: dts: dra72-evm: Configure DSP & IVA clocks for OPP_HIGH
  HACK: ARM: dts: dra7-evm: Configure DSP and IVA clocks for OPP_HIGH
  ti_config_fragments/baseport: Enable CONFIG_REGULATOR
  ARM: dts: k2g: Enable edma
  ARM: common: edma: Switch to platform_driver_register
  ARM: dts: k2g: add clock support
  clk: keystone: add sci-clk driver support
  dt-binding: clock: add k2g clock definitions
  Documentation: dt: Add TI SCI clock
  ARM: dts: am437x-idk-evm: Add opp disable exception for OPP50
  ARM: OMAP2+: opp: Add opp exception checking
  Documentation: dt: omap: opp: Add opp exception binding docs
  ARM: OMAP2+: opp: Fix comment block for opp_def_list_enable_opp
  dmaengine: edma: fix residue race for cyclic

Signed-off-by: Suman Anna <s-anna@ti.com>