do not enforce CONFIG_STM32_CCMEXCLUDE for CONFIG_ARCH_CHIP_STM32F7, macro rename STM32 -> STM32F7, #include corrections

CDC/ACM.  Fix several known problems resulting from merge of USB composite device.  That merge now breaks some of the non-composite USB devices.  These fixes are for CDC/ACM.

Typos

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Networking: When upd_input() cannot process a packet, it returns ERROR so that network drivers may try calling ipv4_input() later.  In this case, it must also set d_len to zero.  Otherwise, all network drivers will assume tht there is also an outgoing packet.  This results in a gratuitous ARP.