tty: serial: samsung_tty: remove spinlock flags in interrupt handlers

Since interrupt handler is called with disabled local interrupts, there
is no need to use the spinlock primitives disabling interrupts as well.
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210315181212.113217-1-krzysztof.kozlowski@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/samsung_tty.c

@@ -715,13 +715,12 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
 	struct s3c24xx_uart_dma *dma = ourport->dma;
 	struct tty_struct *tty = tty_port_tty_get(&ourport->port.state->port);
 	struct tty_port *t = &port->state->port;
-	unsigned long flags;
 	struct dma_tx_state state;
 
 	utrstat = rd_regl(port, S3C2410_UTRSTAT);
 	rd_regl(port, S3C2410_UFSTAT);
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock(&port->lock);
 
 	if (!(utrstat & S3C2410_UTRSTAT_TIMEOUT)) {
 		s3c64xx_start_rx_dma(ourport);
@@ -750,7 +749,7 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id)
 	wr_regl(port, S3C2410_UTRSTAT, S3C2410_UTRSTAT_TIMEOUT);
 
 finish:
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock(&port->lock);
 
 	return IRQ_HANDLED;
 }
@@ -846,11 +845,10 @@ static irqreturn_t s3c24xx_serial_rx_chars_pio(void *dev_id)
 {
 	struct s3c24xx_uart_port *ourport = dev_id;
 	struct uart_port *port = &ourport->port;
-	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock(&port->lock);
 	s3c24xx_serial_rx_drain_fifo(ourport);
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock(&port->lock);
 
 	return IRQ_HANDLED;
 }
@@ -934,13 +932,12 @@ static irqreturn_t s3c24xx_serial_tx_irq(int irq, void *id)
 {
 	struct s3c24xx_uart_port *ourport = id;
 	struct uart_port *port = &ourport->port;
-	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
+	spin_lock(&port->lock);
 
 	s3c24xx_serial_tx_chars(ourport);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock(&port->lock);
 	return IRQ_HANDLED;
 }