ectool: Fix "rwsig dump key_id" hex output
ectool: Fix "rwsig dump key_id" hex output

The ectool command rwsig dump key_id's output was missing zeros in the
hex string output. This is because we print each byte independently
using the naked %x formatter, which will print the minimum hex
characters necessary to represent the independent number provided.

We need to force exactly 2 hex characters for each independent byte
printed.

BRANCH=none
BUG=b:162588911
TEST=# Nocturne
     make BOARD=nocturne_fp build/nocturne_fp/util/ectool
     # Copy build/nocturne_fp/util/ectool to fat32 flash drive
     mkdir /tmp/rem
     mount /dev/sda1 /tmp/rem
     ectool --name=cros_fp rwsig dump key_id | tr -d '\n' | wc -c
     # Identify there are less than 40 chars (39 in my case)
     /tmp/rem/ectool --name=cros_fp rwsig dump key_id | tr -d '\n' | wc -c
     # Identify there are exactly 40 chars
     # Rerun both commands without the byte counting to sanity
     # check the output

Change-Id: I0a43833adb647aa034df87678c9657466cc8aef5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2336865
Commit-Queue: Craig Hesling <383db090fd8ef907a606ac8a9eccd2962bc489cf@chromium.org>
Commit-Queue: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Tested-by: Craig Hesling <383db090fd8ef907a606ac8a9eccd2962bc489cf@chromium.org>
Reviewed-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Auto-Submit: Craig Hesling <383db090fd8ef907a606ac8a9eccd2962bc489cf@chromium.org>

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