PM: hibernate: Drop unnecessary local variable initialization

It is not necessary to intialize the error variable in
create_basic_memory_bitmaps(), because it is only read after
being assigned a value.

Signed-off-by: Wang chaodong <chaodong@nfschina.com>
[ rjw: Subject and changelog rewrite ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>