module: Remove const attribute from alias for MODULE_DEVICE_TABLE

MODULE_DEVICE_TABLE(type, name) creates an alias of type 'extern const
typeof(name)'. If 'name' is already constant the 'const' attribute is
specified twice, which is not allowed in C89 (see discussion at
https://lkml.org/lkml/2017/5/23/1440). Since the kernel is built with
-std=gnu89 clang generates warnings like this:

drivers/thermal/x86_pkg_temp_thermal.c:509:1: warning: duplicate 'const'
  declaration specifier
      [-Wduplicate-decl-specifier]
MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids);
^
./include/linux/module.h:212:8: note: expanded from macro 'MODULE_DEVICE_TABLE'
extern const typeof(name) __mod_##type##__##name##_device_table

Remove the const attribute from the alias to avoid the duplicate
specifier. After all it is only an alias and the attribute shouldn't
have any effect.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

include/linux/module.h

@@ -209,7 +209,7 @@ extern void cleanup_module(void);
 #ifdef MODULE
 /* Creates an alias so file2alias.c can find device table. */
 #define MODULE_DEVICE_TABLE(type, name)					\
-extern const typeof(name) __mod_##type##__##name##_device_table		\
+extern typeof(name) __mod_##type##__##name##_device_table		\
   __attribute__ ((unused, alias(__stringify(name))))
 #else  /* !MODULE */
 #define MODULE_DEVICE_TABLE(type, name)