modpost: strip .o from modname before calling new_module()

new_module() conditionally strips the .o because the modname has .o
suffix when it is called from read_symbols(), but no .o when it is
called from read_dump().

It is clearer to strip .o in read_symbols().

I also used flexible-array for mod->name.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 3dc9e8fa..254c753 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -116,7 +116,6 @@ struct namespace_list {
 
 struct module {
 	struct module *next;
-	const char *name;
 	int gpl_compatible;
 	struct symbol *unres;
 	int from_dump;  /* 1 if module was loaded from *.symvers */
@@ -130,6 +129,7 @@ struct module {
 	struct namespace_list *missing_namespaces;
 	// Actual imported namespaces
 	struct namespace_list *imported_namespaces;
+	char name[];
 };
 
 struct elf_info {