ide: add IDE_HFLAG_NO_DSC host flag

* Add IDE_HFLAG_NO_DSC host flag for hosts that doesn't support DSC overlap.

* Set it in aec62xx (for ATP850UF only) and hpt34x host drivers.

* Convert ide-tape device driver to check for IDE_HFLAG_NO_DSC flag.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/hpt34x.c b/drivers/ide/pci/hpt34x.c
index dfba0d1..48a9ff2 100644
--- a/drivers/ide/pci/hpt34x.c
+++ b/drivers/ide/pci/hpt34x.c
@@ -131,6 +131,7 @@
 
 #define IDE_HFLAGS_HPT34X \
 	(IDE_HFLAG_NO_ATAPI_DMA | \
+	 IDE_HFLAG_NO_DSC | \
 	 IDE_HFLAG_ABUSE_SET_DMA_MODE | \
 	 IDE_HFLAG_NO_AUTODMA)