configure: rename remaining HAVE_EGL_PLATFORM_* guards

Analogous to others earlier, these will be used to control the platform
for more than the EGL driver.

Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
2 files changed