tools/testing/radix-tree/idr-test: add missing MODULE_DESCRIPTION define

tools/testing/radix-tree/idr-test: add missing MODULE_DESCRIPTION define

Userspace builds of the radix-tree testing suite fails because of patch
KUnit: add missing MODULE_DESCRIPTION() macros for lib/test_*.ko.  Add the
proper defines to tools/testing/radix-tree/idr-test.c so
MODULE_DESCRIPTION has a definition.  This allows the build to succeed.

Link: https://lkml.kernel.org/r/20240626232100.306130-1-sidhartha.kumar@oracle.com
Fixes: f069e33dafe1 ("KUnit: add missing MODULE_DESCRIPTION() macros for lib/test_*.ko")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>