staging: sm750fb: merge lynx_share into sm750_dev

Both struct lynx_share and struct sm750_dev reprsent some parts of the
SM750 graphics adapter. There is no point to keep these parts in
different structures.

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