FW has some usecases when it needs to enqueue frames into hardware. In
BE WLAN chips, some hardware TX desc fields are moved into Tx
banks, hence a TX bank is also needed to queue to HW.
Dedicate a bank for FW usage.
Change-Id: I1f19f0ef85aff4c7592b0f07de4631259da743a6
CRs-Fixed: 3016828
Below are the changes in HW headers for E1.5
1) WBM2SW release source enum changed back to lithium values
2) DSCP to tid table num is added in Bank register
3) MCAST ctrl value is moved from Bank to seperate register
Change-Id: I342c451d792b1618dcb62ca9d4c77dcf4d4beeac
