package/mesa3d: Fix optional DRI3 support

DRI3 support is optional in mesa3d, but mesa3d expects it by default,
so add configure options to disable it when necessary and add the
needed dependencies for DRI3 support. Fixes:

===============================
checking for DRI3PROTO... no
configure: error: Package requirements (dri3proto >= 1.0) were not met:

checking for PRESENTPROTO... no
configure: error: Package requirements (presentproto >= 1.0) were not met:

configure: error: Package requirements (x11 xext xdamage xfixes x11-xcb xcb-glx >= 1.8.1
 xcb-dri2 >= 1.8 xcb-dri3 xcb-present xcb-sync xshmfence >= 1.1) were not met:

Package xshmfence was not found in the pkg-config search path.
===============================

This defconfig was broken and fixed by this patch:

BR2_TOOLCHAIN_EXTERNAL=y
BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
BR2_PACKAGE_MESA3D=y
BR2_PACKAGE_MESA3D_DRI_DRIVER_I965=y
BR2_PACKAGE_XORG7=y
BR2_PACKAGE_XSERVER_XORG_SERVER=y
BR2_PACKAGE_XSERVER_XORG_SERVER_MODULAR=y
BR2_PACKAGE_XPROTO_DRI3PROTO=y

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>