Make use of the fact that target_elf_gregset_t is a proper structure.
Note that the kernel's uses an array, and then it has a bunch of defines
to create symbolic offsets. Modulo some reserved fields, which we do
not implement here, this is the same layout as struct user_pt_regs.
Drop ELF_NREG, target_elf_greg_t, and tswapreg.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
190cc717f8