tools: ynl: fix setting presence bits in simple nests

When we set members of simple nested structures in requests
we need to set "presence" bits for all the nesting layers
below. This has nothing to do with the presence type of
the last layer.

Fixes: be5bea1cc0 ("net: add basic C code generators for Netlink")
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240321020214.1250202-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/ynl-gen-c.py

@@ -228,8 +228,11 @@ class Type(SpecAttr):
         presence = ''
         for i in range(0, len(ref)):
             presence = f"{var}->{'.'.join(ref[:i] + [''])}_present.{ref[i]}"
-            if self.presence_type() == 'bit':
-                code.append(presence + ' = 1;')
+            # Every layer below last is a nest, so we know it uses bit presence
+            # last layer is "self" and may be a complex type
+            if i == len(ref) - 1 and self.presence_type() != 'bit':
+                continue
+            code.append(presence + ' = 1;')
         code += self._setter_lines(ri, member, presence)
 
         func_name = f"{op_prefix(ri, direction, deref=deref)}_set_{'_'.join(ref)}"