mailbox: mpfs: ditch a useless busy check

mpfs_mbox_rx_data() already checks if the system controller is busy
before attempting to do anything, so drop the second check before
reading any data.

No functional change intended.

Acked-by: Jassi Brar <jaswinder.singh@linaro.org>
Tested-by: Valentina Fernandez <valentina.fernandezalanis@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

drivers/mailbox/mailbox-mpfs.c

@@ -170,12 +170,10 @@ static void mpfs_mbox_rx_data(struct mbox_chan *chan)
 	if (response->resp_status)
 		return;
 
-	if (!mpfs_mbox_busy(mbox)) {
-		for (i = 0; i < num_words; i++) {
-			response->resp_msg[i] =
-				readl_relaxed(mbox->mbox_base
-					      + mbox->resp_offset + i * 0x4);
-		}
+	for (i = 0; i < num_words; i++) {
+		response->resp_msg[i] =
+			readl_relaxed(mbox->mbox_base
+				      + mbox->resp_offset + i * 0x4);
 	}
 
 	mbox_chan_received_data(chan, response);