drivers/sfi: sfi_acpi.c needs sysfs.h

sfi_acpi.c needs to include linux/sysfs.h for data types.

drivers/sfi/sfi_core.h:66: error: field 'attr' has incomplete type
drivers/sfi/sfi_acpi.c:179: warning: 'struct kobject' declared inside parameter list
drivers/sfi/sfi_acpi.c:179: warning: its scope is only this definition or declaration, which is probably not what you want
drivers/sfi/sfi_acpi.c:182: warning: type defaults to 'int' in declaration of '__mptr'
drivers/sfi/sfi_acpi.c:182: warning: initialization from incompatible pointer type

Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Paul Gortmaker <[e-mail]>

drivers/sfi/sfi_core.h

···
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 */
+
+#include <linux/sysfs.h>
+
 struct sfi_table_key{
 	char	*sig;
 	char	*oem_id;