When calling from_dict() on a hierarchy of nested BER_TLV_IE,
only the first/outer layer of TLV_IE_Collection would get its
'decoded' initialized correctly from the dict. Subsequent layers
were not, as the 'decoded=' was passed as parameter during instance
initialization. If we first instantiate the class and then call the
from_dict() method, the recursive initialization down the full hierarchy
works as expected.
Change-Id: I795a33ed8dfa8454dc9079c189ab7b2ba64a3b72