UPSTREAM: iscsi_ibft: Fix isa_bus_to_virt not working under ARM

The isa_bus_to_virt is only needed under X86 and in fact the code
that sets the ibft_phys_addr is only compiled under X86.

As such lets just ifdef the code.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Vijayendra Suman <vijayendra.suman@oracle.com>
CC: Maurizio Lombardi <mlombard@redhat.com>
CC: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Change-Id: I68b691cbd2f9f44fe8c876a303c5e4a2c38df82b
---
v2: Remove the ibft_phys_addr as it is defined in iscsi_ibft.h
(cherry picked from commit 799206c1)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>