kconfig: use sym_get_choice_menu() in sym_check_prop()

Choices and their members are associated via the P_CHOICE property.

Currently, prop_get_symbol(sym_get_choice_prop()) is used to obtain
the choice of the given choice member.

Replace it with sym_get_choice_menu(), which retrieves the choice
without relying on P_CHOICE.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/menu.c

@@ -263,11 +263,9 @@ static void sym_check_prop(struct symbol *sym)
 					    sym->name);
 			}
 			if (sym_is_choice(sym)) {
-				struct property *choice_prop =
-					sym_get_choice_prop(sym2);
+				struct menu *choice = sym_get_choice_menu(sym2);
 
-				if (!choice_prop ||
-				    prop_get_symbol(choice_prop) != sym)
+				if (!choice || choice->sym != sym)
 					prop_warn(prop,
 						  "choice default symbol '%s' is not contained in the choice",
 						  sym2->name);