arm: zynq: Add support for system reset

Do system reset via slcr registers.

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

arch/arm/mach-zynq/common.h

@@ -18,6 +18,7 @@
 #define __MACH_ZYNQ_COMMON_H__
 
 extern int zynq_slcr_init(void);
+extern void zynq_slcr_system_reset(void);
 
 extern void __iomem *zynq_slcr_base;
 extern void __iomem *zynq_scu_base;