[cpu][netbsd] Fix "undefined: cpuTimes" error at compile time on arm

Fixes #1645

cpu/cpu_netbsd_arm.go

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: BSD-3-Clause
+package cpu
+
+type cpuTimes struct {
+	User uint32
+	Nice uint32
+	Sys  uint32
+	Intr uint32
+	Idle uint32
+}