tty: serial: samsung_tty: Use abs() to simplify some code

Use abs() instead of hand-writing it.

Suggested-by: Walter Harms <wharms@bfs.de>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Message-ID: <7bd165e82ed3675d4ddee343ab373031e995a126.1686412569.git.christophe.jaillet@wanadoo.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: tititiou36

drivers/tty/serial/samsung_tty.c

@@ -24,6 +24,7 @@
 #include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
+#include <linux/math.h>
 #include <linux/module.h>
 #include <linux/ioport.h>
 #include <linux/io.h>
@@ -1485,9 +1486,7 @@ static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport,
 		}
 		quot--;
 
-		calc_deviation = req_baud - baud;
-		if (calc_deviation < 0)
-			calc_deviation = -calc_deviation;
+		calc_deviation = abs(req_baud - baud);
 
 		if (calc_deviation < deviation) {
 			/*