pci: Add boundary check for hose->regions

pci: Add boundary check for hose->regions

Make sure that we don't overflow the hose->regions array, otherwise we
would end up overwriting the hose->region_count field and cause mayhem
to ensue. Also print an error message when we'd be overflowing because
it indicates that there aren't enough regions available and the number
needs to be increased.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>