kukui: scp: Set CPU clock to default before ULPOSC calibration
kukui: scp: Set CPU clock to default before ULPOSC calibration

ULPOSC 1 & 2 calibration may fail if SCP CPU clock selection is
configured to one of them. The SCP reset mechanism does not reset the
clock selection. So before calibration, set CPU to default clock.

BUG=b:125695639
BRANCH=none
TEST=manual
  build and load on kukui, check remoteproc init correctly.
  check SCP uart console command 'ulposc', output non-zero clocks.

Change-Id: I6807017808a663f8e80363dc0672748ab1957978
Signed-off-by: Rong Chang <3a05493f7adfb36d203f663b3bc2ba30e9d6284f@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1538096
Reviewed-by: Yilun Lin <2f2733c7206ea2b76bd2db1905cc5e8a75841c48@chromium.org>
Reviewed-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec