Remove semicolon at the end of define BPF_STACK_TRACE()

The semicolon is usually added when the macro is used. Update both the
macro definition and all uses.

Signed-off-by: Song Liu <songliubraving@fb.com>
diff --git a/examples/tracing/stacksnoop.py b/examples/tracing/stacksnoop.py
index e4bbb51..7b3d018 100755
--- a/examples/tracing/stacksnoop.py
+++ b/examples/tracing/stacksnoop.py
@@ -52,7 +52,7 @@
     char comm[TASK_COMM_LEN];
 };
 
-BPF_STACK_TRACE(stack_traces, 128)
+BPF_STACK_TRACE(stack_traces, 128);
 BPF_PERF_OUTPUT(events);
 
 void trace_stack(struct pt_regs *ctx) {