x86: LLVMLinux: Fix "incomplete type const struct x86cpu_device_id"

Similar to the fix in 40413dc

MODULE_DEVICE_TABLE(x86cpu, ...) expects the struct to be called struct
x86cpu_device_id, and not struct x86_cpu_id which is what is used in the rest
of the kernel code.  Although gcc seems to ignore this error, clang fails
without this define to fix the name.

Code from drivers/thermal/x86_pkg_temp_thermal.c
static const struct x86_cpu_id __initconst pkg_temp_thermal_ids[] = { ... };
MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids);

Error from clang:
drivers/thermal/x86_pkg_temp_thermal.c:577:1: error: variable has
      incomplete type 'const struct x86cpu_device_id'
MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids);
^
include/linux/module.h:145:3: note: expanded from macro
      'MODULE_DEVICE_TABLE'
  MODULE_GENERIC_TABLE(type##_device, name)
  ^
include/linux/module.h:87:32: note: expanded from macro
      'MODULE_GENERIC_TABLE'
extern const struct gtype##_id __mod_##gtype##_table            \
                               ^
<scratch space>:143:1: note: expanded from here
__mod_x86cpu_device_table
^
drivers/thermal/x86_pkg_temp_thermal.c:577:1: note: forward declaration of
      'struct x86cpu_device_id'
include/linux/module.h:145:3: note: expanded from macro
      'MODULE_DEVICE_TABLE'
  MODULE_GENERIC_TABLE(type##_device, name)
  ^
include/linux/module.h:87:21: note: expanded from macro
      'MODULE_GENERIC_TABLE'
extern const struct gtype##_id __mod_##gtype##_table            \
                    ^
<scratch space>:141:1: note: expanded from here
x86cpu_device_id
^
1 error generated.

Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>