mips/ath25: remove legacy __cpuinit section that crept in

We removed __cpuinit support (leaving no-op stubs) quite some time ago.
However this one crept back in as of commit 43cc739f
("MIPS: ath25: add common parts")

Since we want to clobber the stubs soon, get this removed now.

Cc: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>