Revert "netfilter: nft_ct: Use __refcount_inc() for per-CPU nft_ct_pcpu_template."

This reverts commit 4e318e5e which is
commit 5cfe5612 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Iafe640c549acea0962ef9175da7eae77f39311d9
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>