vty: fix 'Unsigned compared against 0' generate_cpu_hex_mask()

Change-Id: I49549439d5bbfbb83954ba92957304b03062d003
Fixes: CID#212137
diff --git a/src/vty/cpu_sched_vty.c b/src/vty/cpu_sched_vty.c
index f608738..35671a9 100644
--- a/src/vty/cpu_sched_vty.c
+++ b/src/vty/cpu_sched_vty.c
@@ -175,7 +175,7 @@
 		if (CPU_ISSET_S(cpu + 3, cpuset_size, cpuset))
 			val |= 0x08;
 
-		if (val >= 0 && val < 10)
+		if (val < 10)
 			*ptr = '0' + val;
 		else
 			*ptr = ('a' - 10) + val;