[Mesa-stable] 17.1 nomination - eglGetDisplay thread safety patches

[Emil Velikov]

Both of these patches should be picked to resolve the issue
illustrated in the bugreport

4ca9ae587c083b6f03feb65b4ce84929109d5d59 "egl/display: only detect the
platform once"
311c09165881111c4a596ca7e7b4bce89b059e0f "egl/display: make platform
detection thread-safe"

https://bugs.freedesktop.org/show_bug.cgi?id=101252

-Emil