linux-user: `getsockopt` on `SO_RCVTIMEO_NEW`/`SO_SNDTIMEO_NEW` writes unexpected `int`

Qemu doesn't appear to recognize the SO_RCVTIMEO_NEW and SO_SNDTIMEO_NEW values for getsockopt with SOL_SOCKET, and the switch in the linux-user do_getsockopt in the SOL_SOCKET case has a default: that does goto int_case where it silently succeeds and writes an int. However, SO_RCVTIMEO_NEW and SO_SNDTIMEO_NEW are expected to write a struct timeval rather than an int, so this results in unexpected values being written.