SF: Allow triple buffering on values above 3

SurfaceFlinger will enable triple buffering only when configstore
propery maxFrameBufferAcquiredBuffers is equal to 3. This is an
issue for some vendors who set maxFrameBufferAcquiredBuffers to 4
and above.

This patch enable "triple buffering" behavior for any value of
maxFrameBufferAcquiredBuffers above or equal to 3.

Bug: 62024458
Test: Manual
Change-Id: I18f1124fdaf2d25611b4e91e6e9177955f82726a