Add header dependencies

- Now that imx-gpu-viv doesn't package the whole world of headers,
depend on mesa for GL headers.

Change-Id: If18a8f1b1049b66ffdba16eb6272c5b9412a4760
diff --git a/debian/control b/debian/control
index 56f7596..33e0111 100644
--- a/debian/control
+++ b/debian/control
@@ -21,6 +21,8 @@
                libdrm-imx-dev (>= 2.4.84+imx),
                wayland-protocols (>= 1.4) [linux-any],
                imx-gpu-viv,
+               libegl1-mesa-dev,
+               libgles2-mesa-dev,
                linux-headers-4.9.51-aiy (>=1),
                libgstreamer1.0-dev (>= 1.12.0),
                gstreamer1.0-plugins-base (>= 1.12.0),