rwsig: Do not jump to RW if "STAY_IN_RO" flag is set
rwsig: Do not jump to RW if "STAY_IN_RO" flag is set

BRANCH=none
BUG=b:156401765
TEST=make buildall -j
TEST=On bloonchipper console:
     > reboot ro
     => stays in RO
TEST=On bloonchipper console:
     > reboot
     => jumps to RW after RO

Signed-off-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Change-Id: I44faa6ed85a671db3d7217562adfd49650229147
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2197622
Reviewed-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>
Reviewed-by: Craig Hesling <383db090fd8ef907a606ac8a9eccd2962bc489cf@chromium.org>

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