arch: x86: ia32: linker.ld: add missing DT sections macro

Generating sections via DT memory attributes did not work for the
platform as only the memory region was created so far.

This change adds the DT_LINKER_SECTION() macro to the linker script so
that the appropriate sections will be generated, too.

Fixes #79085

Signed-off-by: Florian Grandel <fgrandel@code-for-humans.de>