ath10k: Add new debug level for sta related logs

Add new level ATH10K_DBG_STA debug_mask for printing
sta related logs. This will be useful to check the
debug logs of connection and changes related to
station.

Tested-on: QCA9984 hw1.0 PCI 10.4-3.9.0.2-00021

Signed-off-by: Tamizh Chelvam <tamizhr@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1612463738-16542-1-git-send-email-tamizhr@codeaurora.org