[Doc] Remove unused SPV_INTEL_non_constant_addrspace_printf extension (#8264)

Support of this extension was removed from translator in favor of
Khronos extension in KhronosGroup/SPIRV-LLVM-Translator@ac7a7596 As long
as it was never used in compiler pipeline, the design can be removed.

Specification of SPV_EXT_relaxed_printf_string_address_space:
https://github.com/KhronosGroup/SPIRV-Registry/blob/main/extensions/EXT/SPV_EXT_relaxed_printf_string_address_space.asciidoc

Signed-off-by: Maksimova, Viktoria <[email protected]>

Author: vmaksimo