Revert "hw/display/ramfb: initialize fw-config space with xres/ yres"

This reverts commit f79081b4.

Patch has broken byteorder handling: RAMFBCfg fields are in bigendian
byteorder, the reset function doesn't care so native byteorder is used
instead.  Given this went unnoticed so far the feature is obviously
unused, so just revert the patch.

Cc: Hou Qiming <hqm03ster@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 20200429115236.28709-2-kraxel@redhat.com