MAINTAINERS: Also exclude xe for drm-misc

MAINTAINERS: Also exclude xe for drm-misc

When the xe driver was added, it didn't extend the exclude entries for
drm-misc, as done in commit 5a44d50f0072 ("MAINTAINERS: Update drm-misc
entry to match all drivers"). Exclude it like is done for i915 and other
drivers with dedicated maintainers.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250117164529.393503-1-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>