The original commit/discussion adding -fno-dwarf2-cfi-asm refers to
R_PPC64_REL32 relocations not being handled by our module loader:
http://lkml.kernel.org/r/20090224065112.GA6690@bombadil.infradead.org
However, that is now handled thanks to commit 9f751b82b491d
("powerpc/module: Add support for R_PPC64_REL32 relocations").