sysfs: hardcode file size of regular files to PAGE_SIZE.

This makes the files easily accessible in some graphical file browsers (since
they can automatically handle regular files with a size > 0).

Though not all files have a size that large, that is the size that we allocate
for reading and writing, so it makes sense.

fs/sysfs/inode.c

@@ -72,6 +72,7 @@ static struct inode *sysfs_get_inode(struct super_block *sb, int mode, int dev)
 			init_special_inode(inode, mode, dev);
 			break;
 		case S_IFREG:
+			inode->i_size = PAGE_SIZE;
 			inode->i_fop = &sysfs_file_operations;
 			break;
 		case S_IFDIR: