docs/fingerprint: Add a step to prepare screen
docs/fingerprint: Add a step to prepare screen

screen is not distributed as part of the sdk.

BRANCH=none
BUG=none
TEST=Run `sudo emerge screen` and the next step in the doc succeeds
TEST=View Markdown in gitiles

Change-Id: Ic78838d0e9f22c011579484cb784109b7e6d9740
Signed-off-by: Kevin Shelton <7507f71ebb4f01db734916a11086d9489d89295e@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2095751
Reviewed-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Commit-Queue: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec