goldfish-opengl: nuke unused code path in unregister_VkDeviceMemory

The "direct mapped memory never goes to unregister!" seems to be
correct and this seems like dead code.

BUG=233803018
TEST=run ./deqp-vk.memory.*

Change-Id: I17bfa869fca401a350c8b5252b2ee417826ad100
1 file changed