list: add hlist_count_nodes()

list: add hlist_count_nodes()

Add a generic hlist_count_nodes() function and use it in two drivers.

This patch (of 3):

Add a function to count nodes in a hlist.  hlist_count_nodes() is similar
to list_count_nodes().

Link: https://lkml.kernel.org/r/20240104164937.424320-1-pierre.gondois@arm.com
Link: https://lkml.kernel.org/r/20240104164937.424320-2-pierre.gondois@arm.com
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Acked-by: Coly Li <colyli@suse.de>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Martijn Coenen <maco@android.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Todd Kjos <tkjos@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>