ARM: tegra: Fix flow controller accesses

flowctrl_write_cpu_csr uses the cpu halt offsets and vice versa. This patch
fixes this bug.

Reported-by: Dan Willemsen <dwillemsen@nvidia.com>
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
[swarren: This problem was introduced in v3.4-rc1, in commit 26fe681 "ARM:
 tegra: functions to access the flowcontroller", when this file was first
 added]
Signed-off-by: Stephen Warren <swarren@nvidia.com>