cpufreq: rockchip: fix warning caused by passing invalid cpu id

cpufreq: rockchip: fix warning caused by passing invalid cpu id

------------[ cut here ]------------
[  105.026874] WARNING: at drivers/cpufreq.c:290
[  105.026883] Modules linked in: pvrsrvkm(O)
[  105.026900]
[  105.026915] CPU: 0 PID: 1 Comm: init Tainted: G   O    4.4.66 #1875
[  105.026924] Hardware name: Rockchip Sheep board (DT)
[  105.026937] task: ffffffc07b490000 ti: ffffffc07b484000 task.ti:
ffffffc07b484000
[  105.026964] PC is at cpufreq_cpu_get+0x20/0x8c
[  105.026978] LR is at cpufreq_update_policy+0x28/0x130
[  105.026989] pc : [<ffffff80088246bc>] lr : [<ffffff80088273b8>]
pstate: 60400145
[  105.026997] sp : ffffffc07b487a60
[  105.027004] x29: ffffffc07b487a60 x28: ffffffc07b484000
[  105.027017] x27: ffffff8008b82000 x26: 000000000000008e
[  105.027028] x25: 000000000000011d x24: 0000000000000001
[  105.027039] x23: 0000000000000008 x22: 0000000000000008
[  105.027051] x21: ffffff8009166000 x20: ffffff800923cd50
[  105.027063] x19: ffffffc07a71c600 x18: 0000000000ffffeb

Change-Id: I45de2f755617a5a5903dc5f15e289f8705ceb80d
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>