Currently, tx_monitor mode is enabled/disabled for all peers on a
per-pdev basis. Since tx_monitor mode consumes significant amount of
MIPS and reduces throughput, new requirement is to enable/disable
tx_monitor mode on a per-peer basis as well.
Change-Id: Ib70ccd3238dfd5fae1be92a81e9bf91fe441e228
CRs-Fixed: 2500931