comctl32/listview: fix icon spacing calculation [try 2]

[Daniel Jelinski]

2013/1/14 Nikolay Sivov <bunglehead at gmail.com>:
> So on 64bit you want to distinguish two cases:
> - ~0 value of lParam - you use it to reset to default values;
> - all other values including 0xffffffff that will result in the same call
> with both args being -1.

Unless I got something wrong, all other values including 0xffffffff
will result in a call with both args being 65535. Since parameters are
INTs now, 65535 != -1.

The tests show that:
SendMessage(hwnd, LVM_SETICONSPACING, 0, MAKELPARAM(-1,-1));
results in default spacing on 32bit and (65535,65535) on 64bit.
MAKELPARAM(-1,-1) == (DWORD)-1
MAKELONG(-1,-1) == -1