ncs36510: timer.h rename

This fixes an issue as Timer.h is mbed file, thus if this file gets included first,
causes failures.

Author: 0xc0170

targets/TARGET_ONSEMI/TARGET_NCS36510/exceptions.c

@@ -40,7 +40,7 @@
 #include "uart_16c550.h"
 
 #include "memory_map.h"
-#include "timer.h"
+#include "timer_ncs36510.h"
 
 /* Other inclusions */
 #include "types.h"

targets/TARGET_ONSEMI/TARGET_NCS36510/ncs36510_us_ticker_api.c

@@ -28,7 +28,7 @@
 */
 
 #include <stddef.h>
-#include "timer.h"
+#include "timer_ncs36510.h"
 
 #define US_TIMER  TIMER0
 #define US_TICKER TIMER1