MAINTAINERS: remove myself as a VKMS maintainer

I haven't been able to follow or review the work on the driver for some
time now and I don't see the situation improving anytime soon. I'd like
to continue being listed as a reviewer.

Signed-off-by: Melissa Wen <[e-mail]>
Acked-by: Maíra Canal <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

MAINTAINERS

···
 
 DRM DRIVER FOR VIRTUAL KERNEL MODESETTING (VKMS)
 M:	Rodrigo Siqueira <[e-mail]>
-M:	Melissa Wen <[e-mail]>
 M:	Maíra Canal <[e-mail]>
 R:	Haneen Mohammed <[e-mail]>
 R:	Daniel Vetter <[e-mail]>
+R:	Melissa Wen <[e-mail]>
 L:	[e-mail]
 S:	Maintained
 T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git