change rivafb_remove to __devexit

Change rivafb_remove to __deviexit to fix MODPOST warnings:

WARNING: drivers/video/riva/rivafb.o - Section mismatch: reference to
.exit.text:rivafb_remove from .data.rel.local after 'rivafb_driver' (at offset 0x28)
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: James Simmons <jsimmons@infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/riva/fbdev.c

@@ -2104,7 +2104,7 @@ err_ret:
 	return ret;
 }
 
-static void __exit rivafb_remove(struct pci_dev *pd)
+static void __devexit rivafb_remove(struct pci_dev *pd)
 {
 	struct fb_info *info = pci_get_drvdata(pd);
 	struct riva_par *par = info->par;
@@ -2185,7 +2185,7 @@ static struct pci_driver rivafb_driver = {
 	.name		= "rivafb",
 	.id_table	= rivafb_pci_tbl,
 	.probe		= rivafb_probe,
-	.remove		= __exit_p(rivafb_remove),
+	.remove		= __devexit_p(rivafb_remove),
 };