cli-classic: Add new '--fmap-verify' option

Add a new layout option, --fmap-verify, to be used when writing to
flash, which will compare the FMAP on the flash chip to the one in
the file being flashed, and abort if there are any differences.
The comparison ensures that number of regions and start/end addresses
are all identical.

Add documentation for the new option as well.

TEST: tested with the following commands:
flashrom -p internal -r coreboot.rom --fmap-verify -i COREBOOT (fails w/error)
flashrom -p internal -v coreboot.rom --fmap-verify -i COREBOOT (fails w/error)
flashrom -p internal -r coreboot.rom --fmap -i COREBOOT (ok)
flashrom -p internal -w coreboot.rom --fmap-verify -i COREBOOT (fails w/error - no FMAP)
flashrom -p internal -r coreboot.rom (fails w/error, active ME)
flashrom -p internal -r coreboot.rom --ifd -i bios (ok)
flashrom -p internal -w coreboot.rom --fmap-verify -i COREBOOT -N (ok)

Change-Id: I34f69d848869cf236b7e57cf8f60c2aaad79c385
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/89536
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>

util/flashrom.bash-completion.tmpl

@@ -53,6 +53,7 @@ _flashrom()
 		--flash-size
 		--fmap
 		--fmap-file
+		--fmap-verify
 		--ifd
 		--include
 		--output