qemux86-64: support X11 when QEMU is emulating a different GPU than vmware

qemux86-64: support X11 when QEMU is emulating a different GPU than vmware

QEMU is capable of emulating four different VGA adapters: cirrus, std, vmware,
and QXL. By adding the cirrus and fbdev X.Org drivers to the qemux86-64 image,
the image can be made to launch an X server on when cirrus and std are chosen,
in addition to just vmware. (The build of QEMU in OE-Core appears to have QXL
disabled, meaning a driver for it is unnecessary.)

The runqemu script now allows the choice of emulated VGA adapter to be
specified manually, so it's important that qemux86-64 supports any configuration
the user might choose without requiring the image to be rebuilt.

(From OE-Core rev: 1216de77a7f23fa10e34aee1ebe27fcc6a6589c0)

Signed-off-by: Max Eliaser <max.eliaser@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>