MAINTAINERS: fix style in CADENCE I3C MASTER IP entry

Commit ae24f2b6 ("MAINTAINERS: add myself as maintainer of Cadence I3C
master controller driver") slips in some formatting with spaces instead of
tabs, which ./scripts/checkpatch.pl -f MAINTAINERS complains about:

  #7838: FILE: MAINTAINERS:7838:
  M:      Przemysław Gaj <pgaj@cadence.com>

  WARNING: MAINTAINERS entries use one tab after TYPE:
  #7839: FILE: MAINTAINERS:7839:
  S:      Maintained

  WARNING: MAINTAINERS entries use one tab after TYPE:
  #7840: FILE: MAINTAINERS:7840:
  F:      Documentation/devicetree/bindings/i3c/cdns,i3c-master.txt

  WARNING: MAINTAINERS entries use one tab after TYPE:
  #7841: FILE: MAINTAINERS:7841:
  F:      drivers/i3c/master/i3c-master-cdns.c

Fixes: ae24f2b6 ("MAINTAINERS: add myself as maintainer of Cadence I3C master controller driver")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>