[CCID3] Initialize more fields in ccid3_hc_rx_init

The initialization of ccid3hcrx_rtt to 5ms is just a bandaid, I'll continue
auditing the CCID3 HC rx codebase to fix this properly, probably I'll add a
feedback timer as suggested in the CCID3 draft.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>