Similar to to macOS' CF* types and JNI's jobject and derived types,
the EGLDisplay type is declared as a pointer but can contain
non-pointers (see #27054).
Fix it the same way: map EGLDisplay to uintptr in Go.

Fixes #27054

RELNOTE=yes

Change-Id: I6136f8f8162687c5493b30ed324e29efe55a8fd7
Reviewed-on: https://go-review.googlesource.com/c/154417
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>