remoteproc: k3-dsp: Force cast from iomem address space

These memory regions are mapped as Normal Non-Cached which on
does not have the normal IO address space limitations and so this
cast is safe. Add '__force' to explicitly specify that the cast is
intentional to remove a sparse check warning.

Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20241021204557.929823-3-afd@ti.com


Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>