affects software renderer (emu) only.
per EGL spec:
If EGL_MAX_PBUFFER_WIDTH, EGL_MAX_PBUFFER_HEIGHT,
EGL_MAX_PBUFFER_PIXELS, or EGL_NATIVE_VISUAL_ID are specified
in attrib list, then they are ignored
Change-Id: I3d5214ce896986da2f11d2eb1889afc41731eaa6