fbdev: omapfb: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: YueHaibing <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Alexios Zavras <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Allison Randal <[e-mail]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/video/fbdev/omap2/omapfb/vrfb.c

···
 	int i;
 
 	/* first resource is the register res, the rest are vrfb contexts */
-
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	vrfb_base = devm_ioremap_resource(&pdev->dev, mem);
+	vrfb_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(vrfb_base))
 		return PTR_ERR(vrfb_base);