arm: zynq: Move slcr initialization to separate file

Create separate slcr driver instead of polluting common code.

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

diff --cc arch/arm/mach-zynq/Makefile
Simple merge

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

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

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