egl: handle the full attrib list in display::options

egl: handle the full attrib list in display::options

Earlier spec is vague, although EGL 1.5 makes it clear:

     Multiple calls made to eglGetPlatformDisplay with the same
     parameters will return the same EGLDisplay handle.

With this commit we store and compare the full attrib list.

v2 (Emil):
 - Split into separate patches
 - Use EGLBoolean over int masked as such
 - Don't return free'd pointed on calloc failure

Reviewed-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>