ACPICA: Introduce ACPI_ACCESS_BYTE_WIDTH() macro

Sometimes it is useful to find the access_width field value in bytes and
not in bits so add a helper that can be used for this purpose.

Suggested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/actypes.h

@@ -532,11 +532,12 @@ typedef u64 acpi_integer;
 	 strnlen (a, ACPI_NAMESEG_SIZE) == ACPI_NAMESEG_SIZE)
 
 /*
- * Algorithm to obtain access bit width.
+ * Algorithm to obtain access bit or byte width.
  * Can be used with access_width of struct acpi_generic_address and access_size of
  * struct acpi_resource_generic_register.
  */
 #define ACPI_ACCESS_BIT_WIDTH(size)     (1 << ((size) + 2))
+#define ACPI_ACCESS_BYTE_WIDTH(size)    (1 << ((size) - 1))
 
 /*******************************************************************************
  *