cmd/cgo,cmd/fix,misc/cgo: map the EGLConfig C type to uintptr in Go

cmd/cgo,cmd/fix,misc/cgo: map the EGLConfig C type to uintptr in Go

Similarly to EGLDisplay, EGLConfig is declared as a pointer but may
contain non-pointer values.

I believe this is the root cause of https://todo.sr.ht/~eliasnaur/gio/121.

Change-Id: I412c4fbc2eef4aa028534d68bda95db98e3a365d
Reviewed-on: https://go-review.googlesource.com/c/go/+/235817
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>