egl: Use the loader_open_device() helper to do open with CLOEXEC

egl: Use the loader_open_device() helper to do open with CLOEXEC

We've moved the open with CLOEXEC idiom into a helper function, so
call it instead of duplicating the code.

This also replaces a couple of opens that didn't properly do CLOEXEC.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>