ARM: imx6q: move low-power code out of clock driver

The LPM (Low Power Mode) code that currently sits in imx6q clock driver
will be reused by imx6sl.  Let's move it into pm-imx6q.c, so that we
can keep clock driver SoC specific and reuse pm-imx6q.c on imx6sl.

In order to avoid adding another ioremap for CCM block,
imx6q_pm_set_ccm_base() is created to let clock driver set up ccm_base
for pm code.

During the move, the unused CCGR macros get removed.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>