genericx86: add fbdev, modesettings and vesa Xorg drivers

This should ensure that X can start on more hardware.  The range of hardware is
still small as the atom-pc kernel only has limited framebuffer devices currently
(e.g. no nVidia).

(From meta-yocto rev: 8d862c5357b6c0bac78bf9eaa49ff58468d01129)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto-bsp/conf/machine/genericx86.conf

@@ -18,6 +18,9 @@ XSERVER ?= "xserver-xorg \
            xf86-input-keyboard \
            xf86-input-evdev \
            xf86-input-synaptics \
+           xf86-video-fbdev \
+           xf86-video-modesetting \
+           xf86-video-vesa \
            xf86-video-intel \
            mesa-driver-i915 \
            mesa-driver-i965"