fprobe: add missing MODULE_DESCRIPTION() macro

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in samples/fprobe/fprobe_example.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.

Link: https://lore.kernel.org/all/20240601-md-samples-fprobe-v1-1-5d256a956612@quicinc.com/Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

samples/fprobe/fprobe_example.c

@@ -150,4 +150,5 @@ static void __exit fprobe_exit(void)
 
 module_init(fprobe_init)
 module_exit(fprobe_exit)
+MODULE_DESCRIPTION("sample kernel module showing the use of fprobe");
 MODULE_LICENSE("GPL");