kbench_mod: replace use of cpu_has_tsc by boot_cpu_has()

The former one is not available since Linux 4.6 and boot_cpu_has() is
available since a long time.

Signed-off-by: Vincent Bernat <vincent@bernat.im>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kbench_mod.c b/kbench_mod.c
index fc3765c..8ca3755 100644
--- a/kbench_mod.c
+++ b/kbench_mod.c
@@ -458,7 +458,7 @@
 		&flow_src_ip_addr, flow_tos);
 
 #if defined(CONFIG_X86)
-	if (!cpu_has_tsc) {
+	if (!boot_cpu_has(X86_FEATURE_TSC)) {
 		pr_err("X86 TSC is required, but is unavailable.\n");
 		return -EINVAL;
 	}