orangefs: Fix kmemleak in orangefs_prepare_debugfs_help_string()

In the Linux kernel, the following vulnerability has been resolved: orangefs: Fix kmemleak in orangefs_prepare_debugfs_help_string() When insert and remove the orangefs module, then debug_help_string will be leaked: unreferenced object 0xffff8881652ba000 (size 4096): comm "insmod", pid 1701, jiffies 4294893639 (age 13218.530s) hex dump (first 32 bytes): 43 6c 69 65 6e 74 20 44 65 62 75 67 20 4b 65 79 Client Debug Key 77 6f 72 64 73 20 61 72 65 20 75 6e 6b 6e 6f 77 words are unknow backtrace: [<0000000004e6f8e3>] kmalloc_trace+0x27/0xa0 [<0000000006f75d85>] orangefs_prepare_debugfs_help_string+0x5e/0x480 [orangefs] [<0000000091270a2a>] _sub_I_65535_1+0x57/0xf70 [crc_itu_t] [<000000004b1ee1a3>] do_one_initcall+0x87/0x2a0 [<000000001d0614ae>] do_init_module+0xdf/0x320 [<00000000efef068c>] load_module+0x2f98/0x3330 [<000000006533b44d>] __do_sys_finit_module+0x113/0x1b0 [<00000000a0da6f99>] do_syscall_64+0x35/0x80 [<000000007790b19b>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 When remove the module, should always free debug_help_string. Should always free the allocated buffer when change the free_debug_help_string.