Simplify perf target flags. Apparently the event names aren't stable/portable.

mk/platform.mk

@@ -35,26 +35,7 @@ ifeq ($(CFG_OSTYPE), Linux)
   CFG_LDENV := LD_LIBRARY_PATH
   CFG_DEF_SUFFIX := .linux.def
   ifdef CFG_PERF
-	CFG_PERF_TOOL :=\
-	  $(CFG_PERF) \
-	  stat \
-	  -e cycles \
-	  -e instructions \
-	  -e cache-references \
-	  -e cache-misses \
-	  -e branches \
-	  -e branch-misses \
-	  -e bus-cycles \
-	  -e task-clock \
-	  -e page-faults \
-	  -e context-switches \
-	  -e cpu-migrations \
-	  -e kmem:mm_page_alloc \
-	  -e syscalls:sys_enter \
-	  -e sched:sched_switch \
-	  -e fs:do_sys_open \
-	  -i \
-	  -r 3
+	CFG_PERF_TOOL := $(CFG_PERF) stat -i -r 3
   else
     ifdef CFG_VALGRIND
       CFG_PERF_TOOL :=\