package/xen: Force disable SDL for xen-qemu build

Fixes autobuilder issue:
http://autobuild.buildroot.net/results/8bcb80dc93d38bb38ca32ad93d52c22d1176d57e/

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit a5dd72181e1a79ffe65c788a2c1db9acdf6aa933)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
1 file changed