Staging: otus: Add null check and fix coding style issue

This patch removes mixing of declarations and code and adds a null-test
after a kmalloc.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>