Make manual size overrides on effective addresses only work if legal;

Make manual size overrides on effective addresses only work if legal;
otherwise the override is ignored and a warning is output, so correct
code is always generated.

Reported by: vclaudepierre@tiscali.fr
Bugzilla Bug: 40

* x86expr.c (x86_checkea_calc_displen): Output warnings for noreg case;
reorder such that displacement length calculation is done if the warning
is output.
* x86bc.c (x86_bc_insn_resolve): If length was forced but checkea had to
override it, save it always (to avoid multiple warnings).

* addrop.hex: Match corrected code generation.
* addrop.errwarn: Include new warning message.

* ea-warn.asm, ea-warn.errwarn, ea-warn.hex: Test new functionality more
in depth (code thanks to bug reporter).

svn path=/trunk/yasm/; revision=1165