rpcrt4: Remove unreachable code in EmbeddedComplexSize.

[Juan Lang]

Hi James,

>> RPC_FC_ERROR_STATUS_T has a value of 0x10 and therefore isn't a
>> possible value of "flags_type & 0xf" in the switch statement.
>
> This may be a really stupid question, but is it possible to generate
> this condition?

No, it isn't possible.  0xf & (any value) will never produce any value
larger than 0xf.  0x10 > 0xf.
--Juan