wlan: TX DXE Channel descriptor async uncovered cover case fix

When TX CH does not have pending frame when EXIT IMPS, current logic
could not detect descriptor async
Even there is no valid descriptor on DXE TX ring try to detect
descriptor async
- If no pending frame within DXE ring, just check with HW register value
and head descriptor physical address
- If there are some pending frames and no valid descriptor, program
head descriptor to HW register

Change-Id: Ia8089aeedf8bcd39057cc4656c01982e9745f748
CR-Fixed: 409804
1 file changed
tree: 97eb84cee31667ad9710279974e4825247075a46
  1. CORE/
  2. firmware_bin/
  3. riva/
  4. Kconfig
  5. Makefile