mbcs: add .owner to mbcs struct file_operations

Without ".owner = THIS_MODULE" it is possible to crash the kernel
by unloading the mbcs module while someone works with the file.
Fix this by initializing the ‘struct file_operations' ->owner with
THIS_MODULE.

Signed-off-by: Naveen Kumar Parna <parna.naveenkumar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>