add missing entry in SCALABILITY_STRUCTURES
add missing entry in SCALABILITY_STRUCTURES

add SCALABILITY_L2T1h entry that was inadvertently omitted

BUG=aomedia:1838

Change-Id: I9853a7d77ca67c876f5f979c1196090a6e85494e

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom