connector: Use this_cpu operations

The patch was originally in the use cpuops patchset but it needs an
inc_return and is therefore dependent on an extension of the cpu ops.
Fixed up and verified that it compiles.

get_seq can benefit from this_cpu_operations.  Address calculation is
avoided and the increment is done using an xadd.

Cc: Scott James Remnant <scott@ubuntu.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>