board/trab/memory.c: Fix compile problems.

Apply changes from commit 44b4dbed to board/trab/memory.c, too.

Actually we'd need a major cleanup here - as it turns out,
board/trab/memory.c is more or less a verbatim copy of
post/drivers/memory.c ... but then, trab is EOL anyway,r
so this is not worth the effort.

Signed-off-by: Wolfgang Denk <wd@denx.de>