example,vsrc: lower frequency for LED and 7-SEG

* they are updated too fast after the performance improvement of NVBoard

example/vsrc/led.v

@@ -10,7 +10,7 @@ module led(
     if (rst) begin led <= 1; count <= 0; end
     else begin
       if (count == 0) led <= {led[6:0], led[7]};
-      count <= (count >= 50000 ? 32'b0 : count + 1);
+      count <= (count >= 5000000 ? 32'b0 : count + 1);
     end
   end
 

example/vsrc/seg.v

@@ -21,7 +21,7 @@ assign segs[5] = 8'b10111110;
 assign segs[6] = 8'b11100000;
 assign segs[7] = 8'b11111110;
 
-parameter CLK_NUM = 500000;
+parameter CLK_NUM = 5000000;
 
 reg [31:0] count;
 reg [2:0] offset;