x86/PVH: obtain VGA console info in Dom0

A new platform-op was added to Xen to allow obtaining the same VGA
console information PV Dom0 is handed. Invoke the new function and have
the output data processed by xen_init_vga().

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

Link: https://lore.kernel.org/r/8f315e92-7bda-c124-71cc-478ab9c5e610@suse.com


Signed-off-by: Juergen Gross <jgross@suse.com>