qcacmn: Define QDF API for vzalloc and vfree

Define QDF API for virtual memory allocation and free.
Also add new api to get time of the day in microseconds.

Change-Id: I2921055bbb6b5d2a1105d19448b2a10fa2d6ccc5
CRs-Fixed: 3038180

utils/pktlog/linux_ac.c

@@ -125,7 +125,7 @@ int pktlog_alloc_buf(struct hif_opaque_softc *scn)
 	}
 	qdf_spin_unlock_bh(&pl_info->log_lock);
 
-	buffer = vmalloc((page_cnt + 2) * PAGE_SIZE);
+	buffer = qdf_mem_valloc((page_cnt + 2) * PAGE_SIZE);
 	if (!buffer) {
 		return -ENOMEM;
 	}
@@ -182,7 +182,7 @@ void pktlog_release_buf(struct hif_opaque_softc *scn)
 		ClearPageReserved(vpg);
 	}
 
-	vfree(pl_info->buf);
+	qdf_mem_vfree(pl_info->buf);
 	pl_info->buf = NULL;
 }