ACPICA: Resource Mgr: Small fix for buffer size calculation

Fixes a one byte error in the output buffer calculation.
Feng Tang - ACPICA BZ 849:
https://www.acpica.org/bugzilla/show_bug.cgi?id=849

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/rscalc.c

@@ -457,6 +457,15 @@ acpi_rs_get_list_length(u8 * aml_buffer,
 			 * Get the number of vendor data bytes
 			 */
 			extra_struct_bytes = resource_length;
+
+			/*
+			 * There is already one byte included in the minimum
+			 * descriptor size. If there are extra struct bytes,
+			 * subtract one from the count.
+			 */
+			if (extra_struct_bytes) {
+				extra_struct_bytes--;
+			}
 			break;
 
 		case ACPI_RESOURCE_NAME_END_TAG: