ANDROID: gki_defconfig: add FORTIFY_SOURCE, remove SPMI_MSM_PMIC_ARB

Force SPMI_MSM_PMIC_ARB off and enable FORTIFY_SOURCE for GKI

Bug: 142896904
Bug: 134087016
Test: Build/Boot on cuttlefish
Change-Id: Ib6e501f1efee2349d750010a53572dddcb5457c5
Signed-off-by: Todd Kjos <tkjos@google.com>
(cherry picked from 6f2fe74a1b296286a65547150b733dc36837fd8d)
Signed-off-by: Will McVicker <willmcvicker@google.com>