MAINTAINERS: Bluetooth: retire Johan (for now?)

Johan moved to maintaining the Zephyr Bluetooth stack,
and we haven't heard from him on the ML in 3 years
(according to lore), and seen any tags in git in 4 years.
Trade the MAINTAINER entry for CREDITS, we can revert
whenever Johan comes back to Linux hacking :)

Subsystem BLUETOOTH SUBSYSTEM
  Changes 173 / 986 (17%)
  Last activity: 2023-12-22
  Marcel Holtmann <marcel@holtmann.org>:
    Author 91cb4c19 2022-01-27 00:00:00 52
    Committer edcb185f 2022-05-23 00:00:00 446
    Tags 000c2fa2 2023-04-23 00:00:00 523
  Johan Hedberg <johan.hedberg@gmail.com>:
  Luiz Augusto von Dentz <luiz.dentz@gmail.com>:
    Author d03376c1 2023-12-22 00:00:00 241
    Committer da9065ca 2023-12-22 00:00:00 341
    Tags da9065ca 2023-12-22 00:00:00 493
  Top reviewers:
    [33]: alainm@chromium.org
    [31]: mcchou@chromium.org
    [27]: abhishekpandit@chromium.org
  INACTIVE MAINTAINER Johan Hedberg <johan.hedberg@gmail.com>

Link: https://lore.kernel.org/r/20240109164517.3063131-6-kuba@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>