init: delete the __cpuinit related stubs

The __cpuinit support was removed several releases ago in 3.11-rc1 with
commit 22f0a273

 ("init.h: remove __cpuinit
sections from the kernel")

People have had a chance to update their out of tree code, so now we remove
the no-op stubs to ensure no more new use cases can creep back in.

Also delete the mention of __cpuinitdata from the tag script.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>