MA-19859 Gate off core and bus clock slice

The core and bus clocks are default enabled when SoC power on, and
bootloader not gate off the clocks when booting Linux Kernel.

So Linux Kernel is not aware the peripheral clocks are enabled and
still take them as disabled because of enable count is zero.

After we enable GKI, disable_unused_clk does not work. This causes
unused core and bus clocks to remain on, so turn them off here.

Change-Id: If7994c6ea05724f1d16d512c03df6fad1d6c1823
Signed-off-by: Zhipeng Wang <zhipeng.wang_1@nxp.com>