hwf-x86: use edi for passing value to ebx for i386 cpuid

* src/hwf-x86.c [__i386__] (get_cpuid): Use '=D' for regs[1] instead
of '=r'.

On Win32, %ebx can be assigned for '=r' (regs[1]). This results invalid
assembly:
pushl %ebx
movl %ebx, %ebx
cpuid
movl %ebx, %ebx
popl %ebx

So use '=D' (%esi) for regs[1] instead.

• Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>