gpu-viv-bin-mx6q: fix GLESv2 support

gpu-viv-bin-mx6q: fix GLESv2 support

Tested with:
    QMX6 board +
    BR2_TOOLCHAIN_EXTERNAL=y
    BR2_TARGET_GENERIC_GETTY_PORT="ttymxc1"
    BR2_LINUX_KERNEL=y
    BR2_LINUX_KERNEL_CUSTOM_GIT=y
    BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://git.congatec.com/arm/qmx6_kernel.git"
    BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="9bafbcba67f7bb2a48a5e05998cecb1165aa444f"
    BR2_LINUX_KERNEL_DEFCONFIG="qmx6"
    BR2_LINUX_KERNEL_APPENDED_UIMAGE=y
    BR2_LINUX_KERNEL_UIMAGE_LOADADDR="0x10008000"
    BR2_LINUX_KERNEL_INTREE_DTS_NAME="imx6q-qmx6"
    BR2_PACKAGE_QT5=y
    BR2_PACKAGE_QT5BASE_LICENSE_APPROVED=y
    BR2_PACKAGE_QT5BASE_EXAMPLES=y
    BR2_PACKAGE_QT5BASE_OPENGL_LIB=y
    BR2_PACKAGE_QT5BASE_EGLFS=y
    BR2_PACKAGE_QT5BASE_DEFAULT_QPA="eglfs"
    BR2_PACKAGE_QT5BASE_GIF=y
    BR2_PACKAGE_QT5BASE_JPEG=y
    BR2_PACKAGE_QT5BASE_PNG=y
    BR2_PACKAGE_QT5QUICKCONTROLS=y
    BR2_PACKAGE_FREESCALE_IMX=y
    BR2_PACKAGE_FREESCALE_IMX_PLATFORM_IMX6Q=y
    BR2_PACKAGE_GPU_VIV_BIN_MX6Q=y
    BR2_PACKAGE_GPU_VIV_BIN_MX6Q_EXAMPLES=y

Signed-off-by: Jérôme Pouiller <jezz@sysmic.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>