arm: zynq: timer: Replace PSS through PS

The acronym PSS is deprecated by Xilinx. The correct term, which is
also used in Xilinx documentation is PS (processing system).
This is just a search and replace:
 - s/PSS/PS/g
 - s/pss/ps/g

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: Josh Cartwright <josh.cartwright@ni.com>

arch/arm/mach-zynq/common.h

@@ -17,6 +17,6 @@
 #ifndef __MACH_ZYNQ_COMMON_H__
 #define __MACH_ZYNQ_COMMON_H__
 
-void __init xttcpss_timer_init(void);
+void __init xttcps_timer_init(void);
 
 #endif