Fix memory corruption when reading Voodoo ROM

[Vort]

Fixes #131.

[Vort]

I took idea of how to handle len = 3 reads from

Bochs/bochs/iodev/usb/usb_ehci.cc

Lines 896 to 900 in 50258bf

	case 8:
	*((Bit32u *) ((Bit8u *) data + 4)) = val_hi;
	case 4:
	*((Bit32u *) data) = val;
	break;

After further thought, doubts about whether this code will work correctly on big-endian architectures appeared.
However I have no access to such machines, so I can't test it.