selftests: ifs: verify IFS ARRAY BIST functionality

There are two selftest scenarios for ARRAY BIST(Board Integrated System
Test) tests:

1. Perform IFS ARRAY BIST tests once on each CPU.
2. Perform IFS ARRAY BIST tests on a random CPU with 3 rounds.

These are not meant to be exhaustive, but are some minimal tests for
for checking IFS ARRAY BIST.

Reviewed-by: Jithu Joseph <[e-mail]>
Reviewed-by: Kuppuswamy Sathyanarayanan <[e-mail]>
Co-developed-by: Ashok Raj <[e-mail]>
Signed-off-by: Ashok Raj <[e-mail]>
Signed-off-by: Pengfei Xu <[e-mail]>
Acked-by: Jithu Joseph <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/drivers/platform/x86/intel/ifs/test_ifs.sh

···
 readonly IFS_ARRAY_BIST_SCAN_MODE="1"
 readonly IFS_PATH="/sys/devices/virtual/misc/intel_ifs"
 readonly IFS_SCAN_SYSFS_PATH="${IFS_PATH}_${IFS_SCAN_MODE}"
+readonly IFS_ARRAY_BIST_SYSFS_PATH="${IFS_PATH}_${IFS_ARRAY_BIST_SCAN_MODE}"
 readonly RUN_TEST="run_test"
 readonly STATUS="status"
 readonly DETAILS="details"
···
 		test_bad_and_origin_ifs_image "$DEFAULT_IMG_ID"
 		test_ifs_scan_available_imgs
 		test_ifs_same_cpu_loop "$IFS_SCAN_MODE" "$RANDOM_CPU" "$LOOP_TIMES"
+	fi
+
+	if [[ -d "$IFS_ARRAY_BIST_SYSFS_PATH" ]]; then
+		ifs_test_cpus "$SIBLINGS" "$IFS_ARRAY_BIST_SCAN_MODE"
+		test_ifs_same_cpu_loop "$IFS_ARRAY_BIST_SCAN_MODE" "$RANDOM_CPU" "$LOOP_TIMES"
+	else
+		append_log "[$SKIP] No $IFS_ARRAY_BIST_SYSFS_PATH, skip IFS ARRAY BIST scan"
 	fi
 }