[PATCH] scsi: prevent ISA driver from building on PPC32

[Christoph Hellwig]

On Sat, Jul 21, 2018 at 12:58:21PM -0700, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap at infradead.org>
> 
> Prevent drivers from building on PPC32 if they use isa_bus_to_virt(),
> isa_virt_to_bus(), or isa_page_to_bus(), which are not available and
> thus cause build errors.

Please don't introduce weird arch dependencies, and add a
CONFIG_ISA_VIRT_TO_BUS instead.