sysfs: kill unnecessary sysfs_get() in open paths

sysfs: kill unnecessary sysfs_get() in open paths

There's no reason to get an extra reference to sysfs_dirent for an
open file.  Open file has a reference to the dentry which in turn has
a reference to sysfs_dirent.  This is fairly obvious as otherwise open
itself won't be able to access the sysfs_dirent.  Kill the extra
sysfs_get() and matching sysfs_put().

Signed-off-by: Tejun Heo <[email protected]>
Acked-by: Cornelia Huck <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>