Update chromeec submodule to upstream main

Updating from commit id 1e800ac83:
2021-03-01 22:59:54 +0000 - (docs: point md files in master to main/HEAD)

to commit id 4c21b57eb:
2021-07-19 11:36:07 +0000 - (pd: Fix missing polarity_rm_dts in some conditions)

This brings in 3145 new commits.

Change-Id: Iff2e9f766e750070d71644c2f9895ad10e8b1c9a
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56431
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 0 insertions, 0 deletions

diff --git a/3rdparty/chromeec b/3rdparty/chromeec
-Subproject 1e800ac838504c0d2950c7aa90cdfe7bde25154
+Subproject 4c21b57eb9619cc3dc86d11226917d25f62f1bc