x86, iommu: Make all IOMMU's detection routines return a value.

We return 1 if the IOMMU has been detected. Zero or an error number
if we failed to find it. This is in preperation of using the IOMMU_INIT
so that we can detect whether an IOMMU is present. I have not
tested this for regression on Calgary, nor on AMD Vi chipsets as
I don't have that hardware.

CC: Muli Ben-Yehuda <[email protected]>
CC: "Jon D. Mason" <[email protected]>
CC: "Darrick J. Wong" <[email protected]>
CC: Jesse Barnes <[email protected]>
CC: David Woodhouse <[email protected]>
CC: Chris Wright <[email protected]>
CC: Yinghai Lu <[email protected]>
CC: Joerg Roedel <[email protected]>
CC: H. Peter Anvin <[email protected]>
CC: Fujita Tomonori <[email protected]>
Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>

0 files changed, 0 insertions, 0 deletions