net: wwan: iosm: fix driver not working with INTEL_IOMMU disabled

With INTEL_IOMMU disable config or by forcing intel_iommu=off from
grub some of the features of IOSM driver like browsing, flashing &
coredump collection is not working.

When driver calls DMA API - dma_map_single() for tx transfers. It is
resulting in dma mapping error.

Set the device DMA addressing capabilities using dma_set_mask() and
remove the INTEL_IOMMU dependency in kconfig so that driver follows
the platform config either INTEL_IOMMU enable or disable.

Fixes: f7af616c ("net: iosm: infrastructure")
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>