dmaengine: idxd: change bandwidth token to read buffers

dmaengine: idxd: change bandwidth token to read buffers

BugLink: https://bugs.launchpad.net/bugs/1969110
[ Upstream commit 7ed6f1b85fb613e5e44ef3e14d73f2dc96860935 ]

DSA spec v1.2 has changed the term of "bandwidth tokens" to "read buffers"
in order to make the concept clearer. Deprecate bandwidth token
naming in the driver and convert to read buffers in order to match with
the spec and reduce confusion when reading the spec.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163951338932.2988321.6162640806935567317.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 7bebc95196915caa8a020d7cbf736ac278de51b4)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>