Bug#990279: linux-image-5.10.0-7-powerpc64le: Upgrade to 5.10.0-7-powerpc64le from 5.10.0-0.bpo.5-powerpc64le breaks amdgpu

[Nathaniel Filardo <nwfilardo@gmail.com>]

I just now noticed Timothy Pearson's note about reverting the
alignment check patch.  An excellent thread to start pulling on, but I
don't think that is the correct fix in itself.  If the addresses
involved are not 64K aligned but merely 4K aligned, then the IOMMU
will have to open an overly wide aperture to include the misaligned
first (and possibly last) pages.

This may suggest that a fix is needed in userspace to ensure proper
alignment, or the misaligned addresses may be coming from somewhere
else in the kernel itself.  I suspect adding some WARN_ON (or perhaps
WARN_ON_ONCE, just in case) will prove informative.  If time permits,
I'll do that, but please don't wait on me.

Cheers,
--nwf;