The document "ELF for the ARM 64-bit Architecture (AArch64)" at http://infocenter.arm.com/help/topic/com.arm.doc.ihi0056c/IHI0056C_beta_aaelf64.pdf
gives the name as R_AARCH64_TLSDESC_LD64_LO12 (NB: without the trailing "_NC").
This patch fixes the naming, adjusts tests, and modifies the asm printer to remove the VK_NC target flag when expanding TLSDESC_CALLSEQ.