gen_decoder does not check fwinfo against submodule effective width

[alessandrothea]

i.e. in cases where fwinfo's width is smaller than the effective width of the module the node is pointing to,gen_decoders does not warn the user

For example, the following line should have produced an error, as tpgen.xml (not shown here) requires 9 bits for decoding.

  <node id="tpgen" address="0x10000" description="tpgen controls" fwinfo="endpoint;width=0" module="file://tpgen.xml"/>

[alessandrothea]

Fixed in uhal.