net/mlx5: E-switch, Initialize TSAR Qos hardware block before its user vports

First enable TSAR Qos hardware block in device before enabling its
user vports.

This refactor is needed so that vports can be enabled before their
representor netdevice can be created.

While at it, esw_create_tsar() returns error code which was used only to
print error. However esw_create_tsar() already prints warning if it hits
an error.
Hence, remove the redundant warning.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>