lwip_select() does not update fd_set arguments

[t-ikegami]

Describe the bug Usually, select system call will update the passed fd_sets on return, such that bits correspoinding to active fds are on. However, the present eRPC definition of rpc_lwip_select() returns only the result code, and fd_sets (readset/writeset/exceptset) are not kicked-back from RTL8720. I'm not much confident, but IDL should be:

rpc_lwip_select(int32 maxfdp1, in binary readset @nullable, in binary writeset @nullable, in binary exceptset @nullable, in binary timeout @nullable) -> int32 ↓ rpc_lwip_select(int32 maxfdp1, inout binary readset @nullable, inout binary writeset @nullable, inout binary exceptset @nullable, in binary timeout @nullable) -> int32