arm: zynq: Move timer to clocksource interface

Use clocksource timer initialization.

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

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/timer.c
Simple merge