Bluetooth: hci_uart: Remove unnecessary NULL check before release_firmware()

release_firmware() checks for NULL pointers internally.
Remove unneeded NULL check for fmw here.

Signed-off-by: Chen Ni <[e-mail]>
Signed-off-by: Luiz Augusto von Dentz <[e-mail]>

drivers/bluetooth/hci_aml.c

···
 		goto exit;
 
 exit:
-	if (firmware)
-		release_firmware(firmware);
+	release_firmware(firmware);
 	return ret;
 }