If a PPP peer disconnects and then tries to reconnect it will send an 'LCP configure request' packet. The code that handles that scenario seems to be clearing the wrong lcp_state flag (LCP_RX_UP instead of LCP_TX_UP) and thus the nuttx ppp client will keep sending IPCP packets which are rightfully dropped by the new peer since it is still in the LCP negotiation phase.
Reviewers note: Reviewing the changes I also see that these file did not follow the NuttX codings standard. I ran all files through nuttx/tools/indent.sh, manually reviewed all files for coding style issues. I also changed occurrences of non-standard types u8_t, u16_t, and u32_t to the standard uint8_t, uint16_t, and uint32_t.
