lavfi/delogo: 10l forgotten trailing NULL in shorthand.

Regression since de3e0ab3.
lavfi: let gcc realign the stack on public graph driving functions

The functions which actually drive the filter graph by pushing
frames through it need to ensure an aligned stack for SIMD functions.

This fixes a crash in YADIF filter when using a mingw build in a MSVC application.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>