uplink: do not automatically close uplink

The API implies that the caller is responsible for closing the uplink.
Closing the uplink automatically `pouch_gateway_uplink_write()` is
unintuitive and leads to the uplink being closed twice.

Signed-off-by: Sam Friedman <sam@golioth.io>

Author: sam-golioth

include/pouch_gateway/uplink.h

@@ -44,6 +44,8 @@ int pouch_gateway_uplink_write(struct pouch_gateway_uplink *uplink,
 /**
  * Open an uplink for the given downlink context.
  *
+ * The uplink must be closed by a call to @ref pouch_gateway_uplink_close().
+ *
  * @param downlink The downlink context.
  * @return Pointer to the uplink context.
  */

lib/uplink.c

@@ -210,14 +210,7 @@ int pouch_gateway_uplink_write(struct pouch_gateway_uplink *uplink,
         payload += bytes_to_copy;
     }
 
-    if (is_last)
-    {
-        pouch_gateway_uplink_close(uplink);
-    }
-    else
-    {
-        process_uplink(uplink);
-    }
+    process_uplink(uplink);
 
     return 0;
 }