lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT

Now that the minimum supported version of LLVM for building the kernel
has been bumped to 15.0.0, the CLANG_VERSION check for older than 14.0.0
is always false, so remove it.

Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250821-bump-min-llvm-ver-15-v2-10-635f3294e5f0@kernel.org


Signed-off-by: Nathan Chancellor <nathan@kernel.org>