Staging: sxg: Fix to load card on low memory machines

* Fix problem of crash on 50MB machine.
* Fixed dma_addr_t bug, which resolves issues on x86_32 bit machines.

Signed-off-by: LinSysSoft Sahara Team <saharaproj@linsyssoft.com>
Signed-off-by: Christopher Harrer <charrer@alacritech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>