bios_emulator: remove assignment without effect

Assigning a parameter which is not used afterwards has not effect.
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: NSimon Glass <sjg@chromium.org>

drivers/bios_emulator/atibios.c

@@ -606,7 +606,6 @@ int biosemu_run(pci_dev_t pcidev, uchar *bios_rom, int bios_len,
 		    (ulong)(vga_info->BIOSImage) != 0xc0000)
 			free(vga_info->BIOSImage);
 		free(vga_info);
-		vga_info = NULL;
 	}
 
 	return 0;