futility: updater: Clean up hard-coded section names to preserve
futility: updater: Clean up hard-coded section names to preserve

The following sections can be now deleted from hard-coded list:

- RO_PRESERVE: no boards use it.
- RO_FSG: new images have set the PRESERVE flag in CBFS.
- SI_GBE, SI_PDR: already using PRESERVE flag since fw branch is cut.

BUG=b:116326638,chromium:936768
TEST=make clean && make runtests

Change-Id: I99759949104bf4f1c1db3556e273923dcb1c5887
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1902841
Tested-by: Hung-Te Lin <8a7fce4940baad93a69f5073b383c85deed9d9c4@chromium.org>
Auto-Submit: Hung-Te Lin <8a7fce4940baad93a69f5073b383c85deed9d9c4@chromium.org>
Reviewed-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>
Commit-Queue: Hung-Te Lin <8a7fce4940baad93a69f5073b383c85deed9d9c4@chromium.org>

coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot