staging: sm750: remove incorrect __exit annotation

The lynxfb_pci_remove function is used as the 'remove' callback of the driver, and must not be discarded:

lynxfb_pci_remove' referenced in section .data' of drivers/built-in.o: defined in discarded section .exit.text' of drivers/built-in.o

This removes the extraneous annotation.

index 3c7ea95dd9f9..dbbb2f879a29 100644
@@ -1250,7 +1250,7 @@ err_enable:
 	return -ENODEV;
 }
 
-static void __exit lynxfb_pci_remove(struct pci_dev *pdev)
+static void lynxfb_pci_remove(struct pci_dev *pdev)
 {
 	struct fb_info *info;
 	struct lynx_share *share;