faad: always drop byte of padding (fixes #5257)

Also covers #2575 and #11514
Revert "faad: drop byte of padding for raw streams"

This reverts commit 937911d559051522554ac6f0d6d35fc0836d541a which was
obsoleted by commit 0fd580b8c0f1590d2b01a5062b4a1d616cd80e1c.