[PATCH] ahci: do not mangle saved HOST_CAP while resetting controller

Do not mangle with HOST_CAP while resetting controller.  The code is
there for a historical reason.  The mangling breaks controller feature
detection and 0 PORTS_IMPL workaround code.

This problem was spotted by Manoj Kasichainula.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Manoj Kasichainula <manoj@io.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

drivers/ata/ahci.c

@@ -645,8 +645,6 @@ static int ahci_reset_controller(void __iomem *mmio, struct pci_dev *pdev)
 	u32 cap_save, impl_save, tmp;
 
 	cap_save = readl(mmio + HOST_CAP);
-	cap_save &= ( (1<<28) | (1<<17) );
-	cap_save |= (1 << 27);
 	impl_save = readl(mmio + HOST_PORTS_IMPL);
 
 	/* global controller reset */