module: use a structure to encapsulate layout.

Makes it easier to handle init vs core cleanly, though the change is
fairly invasive across random architectures.

It simplifies the rbtree code immediately, however, while keeping the
core data together in the same cachline (now iff the rbtree code is
enabled).

Acked-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

arch/arm/kernel/module-plts.c

@@ -32,7 +32,7 @@ struct plt_entries {
 
 static bool in_init(const struct module *mod, u32 addr)
 {
-	return addr - (u32)mod->module_init < mod->init_size;
+	return addr - (u32)mod->init_layout.base < mod->init_layout.size;
 }
 
 u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val)