msm: net: ecm: debugfs code cleanup

Remove several dentry pointers which are not needed.
Using debugfs_remove_recursive will remove all files in
the driver folder so there is no need to actual save each file pointer.

Change-Id: I506279b19746b7131530f47b480cae874f24b186
Signed-off-by: Talel Atias <tatias@codeaurora.org>