imx-gpu-viv: fix build dependencies when linking against libGAL.so

imx-gpu-viv: fix build dependencies when linking against libGAL.so

Packages like QT5 Base with OpenGL and X support link against libGAL.so
at build time. This results in an error because some X functions used
in libGAL.so aren't referenced as the libXdamage, libXext and libXfixes
packages aren't built and installed into sysroot at the time. Fix this
by adding these three packages as build dependencies of imx-gpu-viv.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>