MAINTAINERS: replace git protocol for github

MAINTAINERS: replace git protocol for github

It was removed time ago:
https://github.blog/changelog/2022-03-15-removed-unencrypted-git-protocol-and-certain-ssh-keys/

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: DOC ML <linux-doc@vger.kernel.org>
Cc: KERNEL ML <linux-kernel@vger.kernel.org>
Signed-off-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250625150231.241687-1-xose.vazquez@gmail.com