MAINTAINERS: Add Maira to VKMS maintainers

I've been contributing to VKMS with improvements, reviews, testing and
debugging. Therefore, add myself as a co-maintainer of the VKMS driver.

Acked-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230508141038.327160-1-mairacanal@riseup.net

Author: mairacanal

MAINTAINERS

@@ -6721,6 +6721,7 @@ F:	drivers/gpu/drm/udl/
 DRM DRIVER FOR VIRTUAL KERNEL MODESETTING (VKMS)
 M:	Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
 M:	Melissa Wen <melissa.srw@gmail.com>
+M:	Maíra Canal <mairacanal@riseup.net>
 R:	Haneen Mohammed <hamohammed.sa@gmail.com>
 R:	Daniel Vetter <daniel@ffwll.ch>
 L:	dri-devel@lists.freedesktop.org