ACPICA: Divergences: reduce access size definitions

ACPICA commit cf27b3c98883d2a15d932016792fcb8272ace96d

The following commit introduces definition of access width to ACPICA.
  Commit: 2bece493
  Subject: ACPI: SPCR: Use access width to determine mmio usage

Actually the access bit width can be calculated via access width. It
would be better to define a macro calculating bit width rather than
defining fixed values. This patch thus cleans up the definitions to
reduce divergences.

Link: https://github.com/acpica/acpica/commit/cf27b3c9


Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>