Revert "usb: gadget: hid: Convert to use list_count()"

This reverts commit 33f00f41 as it
breaks the build.

Link: https://lore.kernel.org/r/20221130131854.35b58b16@canb.auug.org.au
Link: https://lore.kernel.org/r/202211301628.iwMjPVMp-lkp@intel.com


Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>