remove NULL from sysfs_get_dirent

for kernels >= 3.13.0

read:
commit 388975cccaaf11abd47525f664c76891c440481a
updated to linux-3.13
updated to mpss-modules-3.1.4
Merge branch 'vanilla' into devel
updated README to mpss-3.1.4
tested and working on linux-3.13.5
Merge branch 'devel'