erofs: remove unused trace event erofs_destroy_inode

The trace event `erofs_destroy_inode` was added but remains unused. This
unused event contributes approximately 5KB to the kernel module size.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Closes: https://lore.kernel.org/r/20250612224906.15000244@batman.local.home


Fixes: 13f06f48 ("staging: erofs: support tracepoint")
Cc: stable@vger.kernel.org
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250617054056.3232365-1-hsiangkao@linux.alibaba.com