qcacmn: Avoid shadow register access when link is down

When the scheduler thread initiates the WMA_SET_BSSKEY_REQ
we send CMD_UPDATE_RX_REO_QUEUE to REO srng. This is done by
posting a descriptor to the reo command ring and then we
update the HP so that the HW can consume the descriptor.
Avoid accessing HP shadow address when we are in runtime
suspend state. Perform a hif_pm_runtime_get to resume the
link and access the shadow register and once done initiate a
hif_pm_runtime_put to allow device to go into runtime
suspend.

Change-Id: I24c3e046a5769f03a0f1969360cccdbe55b81d45
CRs-Fixed: 2495720

hal/wifi3.0/hal_internal.h

@@ -284,6 +284,9 @@ struct hal_srng {
 	} u;
 
 	struct hal_soc *hal_soc;
+
+	/* Number of times hp/tp updated in runtime resume */
+	uint32_t needs_flush;
 };
 
 /* HW SRNG configuration table */