scsi: advansys needs ISA dma api for ISA support

The advansys drvier uses the request_dma function that is used on ISA
machines for the internal DMA controller, which causes build errors
on platforms that have ISA slots but do not provide the ISA DMA API:

drivers/scsi/advansys.c: In function 'advansys_board_found':
drivers/scsi/advansys.c:11300:10: error: implicit declaration of function 'request_dma' [-Werror=implicit-function-declaration]

The problem now showed up in ARM randconfig builds after commit
6571fb3f ("advansys: Update to version 3.5 and remove compilation
warning") made it possible to build on platforms that have neither
VIRT_TO_BUS nor ISA_DMA_API but that do have ISA.

This adds the missing dependency.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>