nissa: Turn off CONFIG_BRINGUP
nissa: Turn off CONFIG_BRINGUP

CONFIG_BRINGUP by default will not start the CPU, though
the current power sequence code starts automatically.
Turn off CONFIG_BRINGUP in preparation for a fix that
changes the way the power sequence code handles the
starting of the CPU (the power button logic should be used
to control the starting of the CPU).

BUG=b:223113743
TEST=zmake build nivviks; flash & run
BRANCH=none

Signed-off-by: Andrew McRae <44ad1424cfc8411c96d9181798ca41ae55709dfb@google.com>
Change-Id: I496bacf9f5e9da09260fd813aade84eca80dd57b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3626855
Reviewed-by: Peter Marheine <ef0b2c492edde94778d7465bfbaeed52c5be6858@chromium.org>

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