Apply input buffer validation also to AVC and MPEG4 encoders

Input buffer validation is existing only on VPX encoders. This patch
applies the checking also to the other sw video encoders.

Bug: 69065651 Bug: 27569635
Test: run poc with and without the patch.
Test: pass post submit media CTS tests after disabling hw encoders.

Merged-In: I1358df64352577fd6d41cd4bfec18be37c98fe6f
Change-Id: I1358df64352577fd6d41cd4bfec18be37c98fe6f
(cherry picked from commit fed57366)
CVE-2017-13241