lib/logic_iomem: fix sparse warnings

A couple of sparse warnings happened here due to casts on
the prints, a missing static and a missing include. Fix
all of them.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: ca2e3342 ("lib: add iomem emulation (logic_iomem)")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>