[media] rc: fix up and genericize some time unit conversions

The ene_ir driver was using a private define of MS_TO_NS, which is meant
to be microseconds to nanoseconds. The mceusb driver copied it,
intending to use is a milliseconds to microseconds. Lets move the
defines to a common location, expand and standardize them a touch, so
that we now have:

  MS_TO_NS - milliseconds to nanoseconds
  MS_TO_US - milliseconds to microseconds
  US_TO_NS - microseconds to nanoseconds

Reported-by: David Härdeman <david@hardeman.nu>
CC: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c
index 885abdd..1ac4913 100644
--- a/drivers/media/rc/ene_ir.c
+++ b/drivers/media/rc/ene_ir.c
@@ -446,27 +446,27 @@
 
 select_timeout:
 	if (dev->rx_fan_input_inuse) {
-		dev->rdev->rx_resolution = MS_TO_NS(ENE_FW_SAMPLE_PERIOD_FAN);
+		dev->rdev->rx_resolution = US_TO_NS(ENE_FW_SAMPLE_PERIOD_FAN);
 
 		/* Fan input doesn't support timeouts, it just ends the
 			input with a maximum sample */
 		dev->rdev->min_timeout = dev->rdev->max_timeout =
-			MS_TO_NS(ENE_FW_SMPL_BUF_FAN_MSK *
+			US_TO_NS(ENE_FW_SMPL_BUF_FAN_MSK *
 				ENE_FW_SAMPLE_PERIOD_FAN);
 	} else {
-		dev->rdev->rx_resolution = MS_TO_NS(sample_period);
+		dev->rdev->rx_resolution = US_TO_NS(sample_period);
 
 		/* Theoreticly timeout is unlimited, but we cap it
 		 * because it was seen that on one device, it
 		 * would stop sending spaces after around 250 msec.
 		 * Besides, this is close to 2^32 anyway and timeout is u32.
 		 */
-		dev->rdev->min_timeout = MS_TO_NS(127 * sample_period);
-		dev->rdev->max_timeout = MS_TO_NS(200000);
+		dev->rdev->min_timeout = US_TO_NS(127 * sample_period);
+		dev->rdev->max_timeout = US_TO_NS(200000);
 	}
 
 	if (dev->hw_learning_and_tx_capable)
-		dev->rdev->tx_resolution = MS_TO_NS(sample_period);
+		dev->rdev->tx_resolution = US_TO_NS(sample_period);
 
 	if (dev->rdev->timeout > dev->rdev->max_timeout)
 		dev->rdev->timeout = dev->rdev->max_timeout;
@@ -801,7 +801,7 @@
 
 		dbg("RX: %d (%s)", hw_sample, pulse ? "pulse" : "space");
 
-		ev.duration = MS_TO_NS(hw_sample);
+		ev.duration = US_TO_NS(hw_sample);
 		ev.pulse = pulse;
 		ir_raw_event_store_with_filter(dev->rdev, &ev);
 	}
@@ -821,7 +821,7 @@
 	dev->learning_mode_enabled = learning_mode_force;
 
 	/* Set reasonable default timeout */
-	dev->rdev->timeout = MS_TO_NS(150000);
+	dev->rdev->timeout = US_TO_NS(150000);
 }
 
 /* Upload all hardware settings at once. Used at load and resume time */