samples: extend hung_task detector test with semaphore support

samples: extend hung_task detector test with semaphore support

Extend the existing hung_task detector test module to support multiple
lock types, including mutex and semaphore, with room for future additions
(e.g., spinlock, etc.).  This module creates dummy files under
<debugfs>/hung_task, such as 'mutex' and 'semaphore'.  The read process on
any of these files will sleep for enough long time (256 seconds) while
holding the respective lock.  As a result, the second process will wait on
the lock for a prolonged duration and be detected by the hung_task
detector.

This change unifies the previous mutex-only sample into a single,
extensible hung_task_tests module, reducing code duplication and improving
maintainability.

Usage is:

	> cd /sys/kernel/debug/hung_task
	> cat mutex & cat mutex          # Test mutex blocking
	> cat semaphore & cat semaphore  # Test semaphore blocking

Update the Kconfig description to reflect multiple debugfs files support.

Link: https://lkml.kernel.org/r/20250414145945.84916-4-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Zi Li <amaindex@outlook.com>
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Mingzhe Yang <mingzhe.yang@ly.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yongliang Gao <leonylgao@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>