…tion

The QoS orchagent call SAI APIs to get the number of child scheduler groups
and then initialize them.
After that, the size of child scheduler groups vector will be non-zero,
which indicates the child scheduler groups have been initialized and
prevent QoS orchagent from calling SAI APIs.
However, on Mellanox platform, some scheduler groups don't have child group,
leaving size of child scheduler groups always being zero.
This causes QoS orchagent to call the SAI API each time the scheduler group
is handled, which wastes a lot of time especially during fast reboot.

An extra flag indicating whether the child groups have been initialized
is introduced to avoid the redundant calls.

Signed-off-by: Stephen Sun <stephens@nvidia.com>

- Fix compiling errors in ARM
- Remove some redundant log message

Signed-off-by: Stephen Sun <stephens@nvidia.com>

Signed-off-by: Stephen Sun <stephens@nvidia.com>