target/i386: decode address before going back to translate.c

target/i386: decode address before going back to translate.c

There are now relatively few unconverted opcodes in translate.c (there
are 13 of them including 8 for x87), and all of them have the same
format with a mod/rm byte and no immediate.  A good next step is
to remove the early bail out to disas_insn_x87/disas_insn_old,
instead giving these legacy translator functions the same prototype
as the other gen_* functions.

To do this, the X86DecodeInsn can be passed down to the places that
used to fetch address bytes from the instruction stream.  To make
sure that everything is done cleanly, the CPUX86State* argument is
removed.

As part of the unification, the gen_lea_modrm() name is now free,
so rename gen_load_ea() to gen_lea_modrm().  This is as good a name
and it makes the changes to translate.c easier to review.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>