nil: Add a PTE kind for Z32_FLOAT

This values was found by trial-and-error poking at the hardware until it
stopped complaining.  It's not clear if we need separate values for
compressed vs. not.  This appears to work on Turing regardless of what
we set for SET_Z_COMPRESSION.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24326>

src/nouveau/nil/nil_image.c

@@ -177,6 +177,7 @@ tu102_choose_pte_kind(enum pipe_format format, bool compressed)
       else
          return 0x04; // NV_MMU_PTE_KIND_ZF32_X24S8
    case PIPE_FORMAT_Z32_FLOAT:
+      return 0x06;
    default:
       return 0;
    }