omap: iommu: Gracefully fail iommu_enable if no arch_iommu is registered
omap: iommu: Gracefully fail iommu_enable if no arch_iommu is registered

In a modular build of the iommu code it's possible that the arch iommu code
isn't loaded when trying to enable the iommu. Instead of blindly following a
null pointer return -NODEV in that case.

Signed-off-by: Martin Hostettler <54669547a225ff20cba8b75a4adca540eef25858@neutronstar.dyndns.org>
Signed-off-by: Tony Lindgren <1001e8702733cced254345e193c88aaa47a4f5de@atomide.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs