winspool.drv: Write-strings warnings fix

[Andrew Talbot]

Mike McCormack wrote:
> These strings should really be const. IMO, a better fix would be to add
> a cast to cast them back to (char*) than to change their storage class.
> 

The trouble is, if you leave them as they were, you get a write-strings
warning, since you are pointing a writeable pointer at a read-only string). 

But if you cast, thus:

    CHAR *dtype = (LPSTR) "RAW";

... then you swap the write-strings warning for a cast-qual one.

In general, it's a solution that Alexandre has accepted.

-- Andy.