With only single RX buffer there is a high chance that such buffer will
not be processed before new bytes come in over UART. This is why it is
good to have at least two buffers, one which can be processed by SMP
layer, while another is being filled with new incoming bytes.
Add Kconfig option which allows to configure multiple buffers filled
with received UART SMP fragments. Use default value of 2, so we can
safely process already received frame in thread, while new fragment
comes in concurrently.
Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
7451a32e98