video: ssd1307fb: Improve a size determination in ssd1307fb_probe()

Replace the specification of a data structure by a pointer dereference
as the parameter for the operator "sizeof" to make the corresponding size
determination a bit safer according to the Linux coding style convention.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bastian Stender <bst@pengutronix.de>
Cc: Jyri Sarha <jsarha@ti.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

drivers/video/fbdev/ssd1307fb.c

@@ -628,7 +628,8 @@ static int ssd1307fb_probe(struct i2c_client *client,
 		goto fb_alloc_error;
 	}
 
-	ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(struct fb_deferred_io), GFP_KERNEL);
+	ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(*ssd1307fb_defio),
+				       GFP_KERNEL);
 	if (!ssd1307fb_defio) {
 		dev_err(&client->dev, "Couldn't allocate deferred io.\n");
 		ret = -ENOMEM;