tpm: xen-tpmfront: Remove the locality sysfs attribute

Upon deeper review it was agreed to remove the driver-unique
'locality' sysfs attribute before it is present in a released
kernel.

The attribute was introduced in e2683957
during the 3.12 merge window, so this patch needs to go in before
3.12 is released.

The hope is to have a well defined locality API that all the other
locality aware drivers can use, perhaps in 3.13.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>