mlxsw: core_thermal: Add line card id prefix to line card thermal zone name

Add prefix "lc#n" to thermal zones associated with the thermal objects
found on line cards.

For example thermal zone for module #9 located at line card #7 will
have type:
mlxsw-lc7-module9.
And thermal zone for gearbox #3 located at line card #5 will have type:
mlxsw-lc5-gearbox3.

Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>