net/ice/base: introduce Tx rate limiting on port level

net/ice/base: introduce Tx rate limiting on port level

The PSM Configuration has a Rate Limiter for each associated
switch port based on its relative speed from the total BW of
switch ports connected to LAN controller. The rate limiters
will be dynamic get readjusted if switch port speeds are
changed at the root node layer of the scheduler tree. Adding
a function to directly modify the EIR of root node.

Signed-off-by: Shibin Koikkara Reeny <shibin.koikkara.reeny@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>