[U-Boot] Update git on git.denx.de

[Heinrich Schuchardt]

Hello Wolfgang,

when fetching from git.denx.de I got:

$ git remote add efi ssh://gu-efi@git.denx.de/u-boot-efi.git
$ git fetch efi
Enter passphrase for key '/home/user/.ssh/id_rsa.denx':
fatal: protocol error: expected old/new/ref, got 'want
d0bd87612f410a723d5ddb3001e805485e3efb4f side-band-64k ofs-delta
agent=git/2.20.1'

Could you, please, consider upgrading the git server to a current version.

The version installed on git.denx.de dates from March 17th, 2016:
<!-- git web interface version 2.7.4, (C) 2005-2006, Kay Sievers
<kay.sievers at vrfy.org>, Christian Gierke -->
<!-- git core binaries version 2.7.4 -->

Current version is 2.21.0.

Best regards

Heinrich