haven: hh_rm_core: Check payload size in hh_rm_init_connection_buff()

Ensure that the payload being copied to the connection's recv_buff
buffer does not exceed the buffer's maximum size.

Change-Id: Ic0e0b894e7746430916b24f45e583822ccea2748
Signed-off-by: Srinivasarao Pathipati <quic_spathi@quicinc.com>