conf: machine: remove Xserver assignments
conf: machine: remove Xserver assignments

Remove the Xserver assignments in the i.MX6 machine configuration. We
don't support that yet.

Removing these assignments allows to build the image 'core-image-sato'
from poky because the Xserver falls back to the framebuffer driver.

Signed-off-by: Stefan Christ <c04781dbce194802ec6a6311a1200fbcd0141e96@phytec.de>

PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec