selftests: media_tests: return Kselftest Skip code for skipped tests

When media_tests test is skipped because of unmet dependencies and/or
unsupported configuration, it exits with error which is treated as a
fail by the Kselftest framework. This leads to false negative result
even when the test could not be run.

Change it to return kselftest skip code when a test gets skipped to
clearly report that the test could not be run.

Change it to use ksft_exit_skip() when the test is skipped.

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

selftests: media_tests: fix spelling mistake: "iternations" -> "iterations"

Trivial fix to spelling mistake in message text

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

selftests: media_tests: Add SPDX license identifier

Replace GPL license statement with SPDX GPL-2.0 license identifier.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

selftests: media_device_test change it to randomize loop count

Change it to randomize the loop count instead of hardcoded number of times
ioctl is called.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

selftests: media_dcevice_test fix usage information

Fix the incorrect usage information.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

selftests: media_dcevice_test fix to handle ioctl failure case

Fix to print information returned by ioctl only when
it returns success.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

selftests: add a new test for Media Controller API

This test opens user specified Media Device and calls
MEDIA_IOC_DEVICE_INFO ioctl in a loop once every 10
seconds. This test is for detecting errors in device
removal path.

Usage:
sudo ./media_device_test -d /dev/mediaX

While test is running, remove the device and
ensure there are no use after free errors and
other Oops in the dmesg. Enable KaSan kernel
config option for use-after-free error detection.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>