m4v_enc: Fix level setparam issue

nv-review-module multimedia
nv-sub-module mm_misc
nv-target NVIDIA
nv-upstream no
nv-patchtype feature-fix
nv-feature AFWORK-370
nv-proprietary false
nv-upgrade-required TBD

Bug 201380458

Change-Id: I5fc4a934f7db14d8db193889848ba2bb32cfbe29