MIPS: ELF: Deconditionalise ABI flags definitions

Move the `mips_elf_abiflags_v0' structure and FP ABI flag macros outside
#ifndef ELF_ARCH.  These are public interfaces.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13243/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>