binfmt_misc: restore write access before closing files opened by open_exec()

In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: restore write access before closing files opened by open_exec() bm_register_write() opens an executable file using open_exec(), which internally calls do_open_execat() and denies write access on the file to avoid modification while it is being executed. However, when an error occurs, bm_register_write() closes the file using filp_close() directly. This does not restore the write permission, which may cause subsequent write operations on the same file to fail. Fix this by calling exe_file_allow_write_access() before filp_close() to restore the write permission properly.