coresight: core: Fix coresight device probe failure issue

coresight: core: Fix coresight device probe failure issue

It is possibe that probe failure issue happens when the device
and its child_device's probe happens at the same time.
In coresight_make_links, has_conns_grp is true for parent, but
has_conns_grp is false for child device as has_conns_grp is set
to true in coresight_create_conns_sysfs_group. The probe of parent
device will fail at this condition. Add has_conns_grp check for
child device before make the links and make the process from
device_register to connection_create be atomic to avoid this
probe failure issue.

Cc: [email protected]
Suggested-by: Suzuki K Poulose <[email protected]>
Suggested-by: Mike Leach <[email protected]>
Signed-off-by: Mao Jinlong <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Added Cc stable ]
Signed-off-by: Suzuki K Poulose <[email protected]>