Packed vector ranges declared with negative parameters

Created by: mcockrell-google

When some parameters are declared as 0 signals are declared with negative indexes:

riscv_core.sv:105       Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_master_type_o' is ascending, should be descending
riscv_core.sv:137       Vector range '[N_EXT_PERF_COUNTERS - 1:0]' ([-1:0]) of 'ext_perf_counters_i' is ascending, should be descending
riscv_core.sv:219       Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_type_ex' is ascending, should be descending
riscv_cs_registers.sv:133       Vector range '[N_EXT_CNT - 1:0]' ([-1:0]) of 'ext_counters_i' is ascending, should be descending
riscv_decoder.sv:116    Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_type_o' is ascending, should be descending
riscv_decoder.sv:119    Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_flags_src_o' is ascending, should be descending
riscv_id_stage.sv:159   Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_type_ex_o' is ascending, should be descending
riscv_id_stage.sv:361   Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_type' is ascending, should be descending
riscv_id_stage.sv:373   Vector range '[WAPUTYPE - 1:0]' ([-1:0]) of 'apu_flags_src' is ascending, should be descending
riscv_prefetch_buffer.sv:73     Vector range '[0:DEPTH - 1]' ([0:3]) of 'addr_n' is ascending, should be descending
riscv_prefetch_buffer.sv:74     Vector range '[0:DEPTH - 1]' ([0:3]) of 'rdata_n' is ascending, should be descending
riscv_prefetch_buffer.sv:75     Vector range '[0:DEPTH - 1]' ([0:3]) of 'valid_n' is ascending, should be descending
riscv_prefetch_buffer.sv:76     Vector range '[0:1]' of 'is_hwlp_n' is ascending, should be descending

This causes issues in various synthesis tools.