Removed the need for the CSP_MTU define!
Removed the need for the CSP_MTU define!

From now on, the MTU must be checked by all interface implementations.
 in the RX function, the call to csp_buffer_net(size) should catch if a too large frame is received for the current allocation in csp_buffer.c
 in the TX function, the packet->size must be verified to be below that the interface driver can handle.
 
User-space should no longer just allocate sizeof(csp_packet_t)! This is WRONG! They should call csp_buffer_new(sizeof(data-to-transmit))!
The csp_buffer_new(sizeof(csp_packet_t)) will still work, since the size is about 50-60 bytes, but is less secure, since it does not catch situations when the buffer size is set to small.

pacheco017/libcsp,pacheco017/libcsp,kubostech/KubOS,marshall/libcsp,Psykar/kubos,GomSpace/libcsp,GomSpace/libcsp,Psykar/kubos,libcsp/libcsp,pacheco017/libcsp,Psykar/kubos,marshall/libcsp,Psykar/kubos,satlab/libcsp,Psykar/kubos,kubostech/KubOS,satlab/libcsp,satlab/libcsp,libcsp/libcsp,GomSpace/libcsp,Psykar/kubos,Psykar/kubos,pacheco017/libcsp,marshall/libcsp