drivers: fix up various ->llseek() implementations

Fix up a few ->llseek() implementations that won't deal with SEEK_HOLE/SEEK_DATA
properly.  Make them future proof so that if we ever add new options they will
return -EINVAL.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/macintosh/nvram.c

@@ -21,12 +21,16 @@
 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
 {
 	switch (origin) {
+	case 0:
+		break;
 	case 1:
 		offset += file->f_pos;
 		break;
 	case 2:
 		offset += NVRAM_SIZE;
 		break;
+	default:
+		offset = -1;
 	}
 	if (offset < 0)
 		return -EINVAL;