samples/bpf: Fix trailing semicolon

The trailing semicolon is an empty statement that does no operation.
Removing it since it doesn't do anything.
Signed-off-by: Luis de Bethencourt <luisbg@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

samples/bpf/xdp_monitor_kern.c

@@ -104,7 +104,7 @@ struct xdp_exception_ctx {
 SEC("tracepoint/xdp/xdp_exception")
 int trace_xdp_exception(struct xdp_exception_ctx *ctx)
 {
-	u64 *cnt;;
+	u64 *cnt;
 	u32 key;
 
 	key = ctx->act;