add a way to access the version string of the h/w implementation of EGL

we use a hidden egl extension. the version string is printed
in SF's dumpsys log.

Change-Id: I123eb4bde6de462bb2404c67b74d6d6219a48d6a
diff --git a/opengl/specs/README b/opengl/specs/README
index 2fa2587..16b278f 100644
--- a/opengl/specs/README
+++ b/opengl/specs/README
@@ -9,4 +9,5 @@
 0x3140               EGL_ANDROID_image_native_buffer
 0x3141               (unused)
 0x3142               EGL_ANDROID_recordable
-0x3143 - 0x314F      (unused)
+0x3143               EGL_VERSION_HW_ANDROID (internal use)
+0x3144 - 0x314F      (unused)