resource: add missing MODULE_DESCRIPTION()

Fix the 'make W=1' warning:
WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/resource_kunit.o

Link: https://lkml.kernel.org/r/20240529-md-kernel-resource_kunit-v1-1-bb719784b714@quicinc.com


Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>