ARM: rockchip: fix broken build

ARM: rockchip: fix broken build

The following was seen in branch[0] build.

arch/arm/mach-rockchip/platsmp.c:154:23: error:
    'rockchip_secondary_startup' undeclared (first use in this function)

branch[0]:
git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git
v4.3-armsoc/soc

The broken build is caused by the commit fe4407c0dc58
("ARM: rockchip: fix the CPU soft reset").

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
The breakage was a result of it being wrongly merged in my branch with
the cache invalidation rework from Russell 02b4e2756e01c
("ARM: v7 setup function should invalidate L1 cache").

Signed-off-by: Heiko Stuebner <heiko@sntech.de>