soc/intel/apollolake: Add config option for enabling hotplug

PcieRpHotPlug in apollolake UPD is default enabled. This change adds a
config option to enable hotplug only if explicitly requested by
mainboard. This changes the default behavior on all apollolake boards
to have hotplug disabled.

BUG=b:74633273
BRANCH=reef,coral

Change-Id: I572c054d31aaf5d43a79c4b1773ec9356da48d9d
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/25187
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2 files changed