arm/mach-rockchip: 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 a7a2b311
("ARM: rockchip: add smp bringup code").

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

Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>