avcodec/hevc: make *ps_id unsigned

Fixes integer overflow
Fixes out of array accesses
Fixes 2f65e7dbd02a12f426a423bd7bf880b4-signal_sigsegv_127c952_2793_cov_2517424539_RPLM_A_qualcomm_4.bit
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
