wil6210: clear PAL_UNIT_ICR part of device reset

When FW starts running it can get D0 to D3 interrupt that is a leftover
from previous system suspend while FW was not running.
As this interrupt is not relevant anymore, clear it part of device reset
procedure.

Signed-off-by: Dedy Lansky <qca_dlansky@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>