freedreno/decode: fix possible overflow

freedreno/decode: fix possible overflow

```
../src/freedreno/decode/rddecompiler.c:242:65: error: 'sscanf' may overflow; destination buffer in argument 3 has size 32, but the corresponding specifier may require size 33 [-Werror,-Wfortify-source]
         if (sscanf(info->name, "%32[A-Z0-6_][%32[x0-9]].%32s", reg_name,
                                                                ^
../src/freedreno/decode/rddecompiler.c:243:21: error: 'sscanf' may overflow; destination buffer in argument 4 has size 32, but the corresponding specifier may require size 33 [-Werror,-Wfortify-source]
                    reg_idx, field_name) != 3) {
                    ^
../src/freedreno/decode/rddecompiler.c:243:30: error: 'sscanf' may overflow; destination buffer in argument 5 has size 32, but the corresponding specifier may require size 33 [-Werror,-Wfortify-source]
                    reg_idx, field_name) != 3) {
                             ^
```

Reviewed-by: Rob Clark <robclark@freedesktop.org>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22015>