Emma stepped back from VC4 maintenance a while ago, and
all patches are now merged through drm-misc.

Drop Emma's tree from MAINTAINERS.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621131926.3133484-2-dave.stevenson@raspberrypi.com