staging: sm750fb: replace lynx_share with sm750_dev in lynxfb_par

Use sm750_dev instead of lynx_share in the private data of the
frambuffer device.

Signed-off-by: Mike Rapoport <mike.rapoport@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>