samples: use K_MSEC with k_sleep()

Couple of samples missing the conversion.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

samples/basic/blink_led/src/main.c

@@ -89,6 +89,6 @@ void main(void)
 			}
 		}
 
-		k_sleep(MSEC_PER_SEC * 4U);
+		k_sleep(K_MSEC(MSEC_PER_SEC * 4U));
 	}
 }

samples/basic/fade_led/src/main.c

@@ -74,6 +74,6 @@ void main(void)
 			}
 		}
 
-		k_sleep(MSEC_PER_SEC);
+		k_sleep(K_MSEC(MSEC_PER_SEC));
 	}
 }

samples/basic/rgb_led/src/main.c

@@ -104,7 +104,7 @@ void main(void)
 						printk("pin 2 write fails!\n");
 						return;
 					}
-					k_sleep(MSEC_PER_SEC);
+					k_sleep(K_MSEC(MSEC_PER_SEC));
 				}
 			}
 		}

samples/basic/servo_motor/src/main.c

@@ -66,6 +66,6 @@ void main(void)
 			}
 		}
 
-		k_sleep(MSEC_PER_SEC);
+		k_sleep(K_MSEC(MSEC_PER_SEC));
 	}
 }