dmaengine: idxd: Update calculation of group offset to be more readable

mainline inclusion
from mainline-v5.11
commit 5a712701
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I596WO


CVE: NA

Intel-SIG: commit 5a712701 dmaengine: idxd: Update calculation of group offset to be more readable.
Incremental backporting patches for DSA/IAA on Intel Xeon platform.

--------------------------------

Create helper macros to make group offset calculation more readable.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/160407294683.839093.10740868559754142070.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>