ARM: zynq: Move of_clk_init from clock driver

Move of_clk_init() from clock driver to enable
options not to use zynq clock driver.
Use for example fixed clock setting.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

diff --cc arch/arm/mach-zynq/common.c
Simple merge

diff --cc drivers/clk/zynq/clkc.c
Simple merge