Fix the error handling of the following two functions:
ihk_device_get_cpu_topology: Returns NULL when not found,
valid non-NULL pointer when found
get_cache_topology: Returns NULL when not found,
valid non-NULL pointer when found,
minus error number on error
Change-Id: Ied13a61d4ab0c314477c45ea659ff2b798ad97ee
Fujitsu: POSTK_DEBUG_TEMP_FIX_21