ramoops: fix types, remove typecasts

Cc: Ahmed S. Darwish <darwish.07@gmail.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>