linux-imx

csky: Init pmu as a device

This patch change the csky pmu initialization from arch init to
device init. The pmu can be configued with information from
device tree(pmu device name, irq number and etc.).

Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <guoren@kernel.org>