Improve CPU identification for POWER processors

Currently gopsutils fails to indentify the POWER processors family,
returning an almost empty Info() structure.

This patch improves the POWER identification without changing what is
available for x86.

cpu/cpu_linux.go

@@ -144,10 +144,22 @@ func Info() ([]InfoStat, error) {
 			c.Family = value
 		case "model":
 			c.Model = value
-		case "model name":
+		case "model name", "cpu":
 			c.ModelName = value
-		case "stepping":
-			t, err := strconv.ParseInt(value, 10, 64)
+			if strings.Contains(value, "POWER8") ||
+			   strings.Contains(value, "POWER7") {
+				c.Model = strings.Split(value, " ")[0]
+				c.Family = "POWER"
+				c.VendorID = "IBM"
+			}
+		case "stepping", "revision":
+			val := value
+
+			if key == "revision" {
+				val = strings.Split(value, ".")[0]
+			}
+
+			t, err := strconv.ParseInt(val, 10, 64)
 			if err != nil {
 				return ret, err
 			}