Revert "drm/ttm: add ttm_bo_pin()/ttm_bo_unpin() v2"

This reverts commit 5f6d5b58 which is
commit deb0814b upstream.

It breaks the Android kernel abi, and is not needed for any Android
devices at this time.  If it is needed in the future, it can be brought
back in an abi-safe way.

Bug: 161946584
Change-Id: I16e61ac3c2787d37a4eac447fa7fa0e8bfdc804e
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>