kvmconfig: add virtio-gpu to config fragment

virtio-gpu is used for VMs, so add it to the kvm config.
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org
[expanded "frag" to "fragment" in summary]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

kernel/configs/kvm_guest.config

@@ -29,3 +29,4 @@ CONFIG_NET_9P_VIRTIO=y
 CONFIG_SCSI_LOWLEVEL=y
 CONFIG_SCSI_VIRTIO=y
 CONFIG_VIRTIO_INPUT=y
+CONFIG_DRM_VIRTIO_GPU=y