Revert "qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()"

This reverts commit 6206b798.

That patch added additional spin_{un}lock_bh(), which was harmless
but pointless. The orginal code path has guaranteed the pair of
spin_{un}lock_bh().

We'd better revert it before we find the exact root cause of the
bug_on mentioned in that patch.

Fixes: 6206b798

 ("qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()")
Cc: David S. Miller <davem@davemloft.net>
Cc: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Jia He <justin.he@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>