WRED thresholds can be specified in bytes if the TM leaf
node supports it. Also extend WRED thresholds to 32 bits from 16.
TM capability (port/level/queue) fields cman_wred_packet_mode_supported and
cman_wred_byte_mode_supported, when non-zero, indicate support for WRED
thresholds in packets and bytes respectively.
The packet_mode member of struct rte_tm_wred_params, when non-zero,
indicates that the min and max thresholds are specified in
packets and when zero, indicates that the min and max thresholds
are specified in bytes.
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>