bpf: Simplify bool comparison

Fix the following coccicheck warning:

./tools/bpf/bpf_dbg.c:893:32-36: WARNING: Comparison to bool.
Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NJiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1612777416-34339-1-git-send-email-jiapeng.chong@linux.alibaba.com

tools/bpf/bpf_dbg.c

@@ -890,7 +890,7 @@ static int bpf_run_stepping(struct sock_filter *f, uint16_t bpf_len,
 	bool stop = false;
 	int i = 1;
 
-	while (bpf_curr.Rs == false && stop == false) {
+	while (!bpf_curr.Rs && !stop) {
 		bpf_safe_regs();
 
 		if (i++ == next)