Revert "Drop max texture cache size from 12x to 5x"

Bug: 155002050
Test: Manual - scroll Pchome app

This reverts commit 05ac5164.

Reason for revert: When running Pchome, this change resulted in poor
performance while scrolling. Every frame appears to be uploading
several textures, potentially the same textures over and over again.

Change-Id: I0fc7216e16f783051d1bd87af764c1a6f361c138