Simplify network % get_num_params()

Author: milancurcic

src/nf/nf_network_submodule.f90

@@ -373,10 +373,7 @@ pure module function get_num_params(self) result(num_params)
     class(network), intent(in) :: self
     integer :: n, num_params
 
-    num_params = 0
-    do n = 1, size(self % layers)
-      num_params = num_params + self % layers(n) % get_num_params()
-    end do
+    num_params = sum(self % layers % get_num_params())
 
   end function get_num_params