yocto-bsp: fix multi-provider error in qemu arch template

While testing the fix for [YOCTO #2222] I noticed a new build error
that wasn't there in previous testing:

ERROR: Multiple .bb files are due to be built which each provide virtual/libgl

The build still completed and produced a good image, but an error
message was displayed, which this patch removes.

Signed-off-by: Tom Zanussi <tom.zanussi@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf b/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf
index 003ead198c..61ba8429e7 100644
--- a/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf
+++ b/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf
@@ -9,6 +9,7 @@ PREFERRED_PROVIDER_virtual/kernel ?= "{{=preferred_kernel}}"
 PREFERRED_VERSION_{{=preferred_kernel}} ?= "{{=preferred_kernel_version}}%"
 
 PREFERRED_PROVIDER_virtual/xserver ?= "xserver-xorg"
+PREFERRED_PROVIDER_virtual/libgl ?= "mesa-dri"
 
 {{ input type:"choicelist" name:"qemuarch" prio:"5" msg:"Which qemu architecture would you like to use?" default:"i386" }}
 {{ input type:"choice" val:"i386" msg:"i386    (32-bit)" }}