flashrom.8.tmpl: Add man entry for --extract

This is a follow up change of CB:52450

Signed-off-by: Daniel Campello <campello@chromium.org>
Change-Id: Icc068f5545b6f30ac390b7b815a31e2d61bf4789
Reviewed-on: https://review.coreboot.org/c/flashrom/+/52892
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
1 file changed