configs: pandaboard: use mdev for automatic module loading

The omap2plus kernel defconfig builds most drivers as modules, so we need
(automatic) module loading to be able to use usb/display/..

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/pandaboard_defconfig

@@ -3,6 +3,7 @@ BR2_cortex_a9=y
 BR2_ARM_ENABLE_NEON=y
 BR2_ARM_ENABLE_VFP=y
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_4=y
+BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV=y
 BR2_TARGET_GENERIC_GETTY_PORT="ttyO2"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="board/pandaboard/post-image.sh"
 BR2_LINUX_KERNEL=y