generation of divxu opcode in h8300-hms

[Kazu Hirata]

Hi Sanjiv,

> That's what my question is. why its not for TARGET_H8300 also?

udivmodqi4 in h8300.md can be used on H8/300.  I will remove the
restriction that it can only be used on H8/300H and H8/S.  However,
16-bit/8-bit unsigned division still requires udivmodhi4, which is
only supported on H8/300H and H8/S.  I am now looking into a way to
generate divxu.b for 16-bit/8-bit division.

Kazu Hirata