hevc: clip pixels when transquant bypass is used

Fixes: asan_stack-oob_eae8e3_7333_WPP_B_ericsson_MAIN10_2.bit
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

This is a more proper fix than 5856bca360c5bc3e340a357d91b1f993c80a7bea

The reconstructed picture should always be clipped (see section 8.6.5),
previously we did not clip coding units where
cu_transquant_bypass_flag == 1

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
hevc: remove useless clip in FUNC(sao_band_filter)()

The src buffer should only contain values in the interval
[0, (1 << BIT_DEPTH) - 1]. Since shift = (BIT_DEPTH - 5), src[x] >> shift
must be in the interval [0, 31], so no clip is needed.

This removes the code that was changed in 5856bca360c5bc3e340a357d91b1f993c80a7bea
as the clip that was repositioned in that commit is removed

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