kernel: config: 6.6: disable ZSTD debug info compression by default

When kernel 6.6 is being compiled with GCC13 it will prompt for:
Compressed Debug information
> 1. Don't compress debug information (DEBUG_INFO_COMPRESSED_NONE)
  2. Compress debugging information with zlib (DEBUG_INFO_COMPRESSED_ZLIB)
  3. Compress debugging information with zstd (DEBUG_INFO_COMPRESSED_ZSTD) (NEW)

This is because kernel now also has support for compressing debug info
with ZSTD, so add the missing symbol and disable it by default.

Signed-off-by: Robert Marko <robimarko@gmail.com>