package/nvidia-driver: install an egl.pc

A lot of packages expect an egl.pc to decide that EGL is available. So,
provide one.

As suggested by Alexandre, use the one from nvidia-tegra23 as template.

Reported-by: Alexandre Maumené <alexandre@maumene.org>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Alexandre Maumené <alexandre@maumene.org>
Cc: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>