wil6210: unmask RX_HTRSH interrupt only when connected

RX_HTRSH interrupt sometimes triggered during device reset
procedure.
To prevent handling this interrupt when not required, unmask
this interrupt only if we are connected and mask it when
disconnected.

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