ide-generic: add missing hwif->chipset setup

hwif->chipset need to be set properly or ide-generic driver will break once
we make a final step in fixing host drivers' dependence on ide_hwifs[].

Problem was catched early thanks to IDE tree exposure in -mm / -next trees
and reported by people listed people (thank you guys!).
Reported-by: "John Keller" <jpk@sgi.com>
Reported-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Reported-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-generic.c

@@ -125,6 +125,7 @@ static int __init ide_generic_init(void)
 			memset(&hw, 0, sizeof(hw));
 			ide_std_init_ports(&hw, io_addr, io_addr + 0x206);
 			hw.irq = ide_default_irq(io_addr);
+			hw.chipset = ide_generic;
 			ide_init_port_hw(hwif, &hw);
 
 			idx[i] = i;