chain: fix alignment of atomic integers in bitcoind conn struct
chain: fix alignment of atomic integers in bitcoind conn struct

As reported by https://github.com/lightningnetwork/lnd/issues/5196, the
new atomic integer isn't properly aligned which can caus panics on
32-bit operating systems.. Tof fix this issue, we move the 64-bit
integer to lay after the two 32-bit integers at the top of the struct.

btcsuite/btcwallet,btcsuite/btcwallet