ASoC: cs35l56-test: Fix missing module namespace import

ASoC: cs35l56-test: Fix missing module namespace import

The test must import namespace "EXPORTED_FOR_KUNIT_TESTING".

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: d0ab89951197 ("ASoC: cs35l56: Add KUnit testing of cs35l56_set_fw_suffix()")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202601221843.kS9IMZ0E-lkp@intel.com/
Link: https://patch.msgid.link/20260123111354.1931986-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>