staging: sm7xxfb: use module init and exit

use module_init() and module_exit() instead of module_pci_driver
and at the same time make way for use of kernel boot parameters.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>