reef: ensure board can boot again after entring G3 after SW sync
reef: ensure board can boot again after entring G3 after SW sync

When SW sync is enabled and the board enters G3 after being up
there was no way to boot the board again because the
system_jumped_to_this_image() check disallowed the pmic startup
sequence. One needs to check if the pmic is also already on
before bailing on the pmic startup sequence.

BUG=chrome-os-partner:56530
BRANCH=None
TEST=Booted. Jumped to RW EC. Shutdown system. Can boot again once
     G3 entered.

Change-Id: I71670ceee09536a282479d1eca6a3ce264f0f5d3
Signed-off-by: Aaron Durbin <af0622ab041e8b0f8e5819838dcc93898196e71f@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/374080
Reviewed-by: Furquan Shaikh <6be5c96c464778f89679b1062a2e0a6af93d2aa5@chromium.org>

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