msm: cleanup and minor fixes for PFT driver

remove unused symlink hook.
free open-file-list on driver exit.
check return value of pft_add_file().

Change-Id: Ida1e4351742ae62cafb2ffa49727f490709351e2
Signed-off-by: Amir Samuelov <amirs@codeaurora.org>
1 file changed