Get rid of while loop in freertos rpmsg init function

[Hadatko]

Hi @MichalPrincNXP,
do you think we can get rid of this while loop using some rtos specific call? For example wait for event.
I think we would need change rpmsg itself. There can be bm poll, wait functions and freertos wait.
BM poll is rpmsg_lite_is_link_up(s_rpmsg)
BM wait can be: while (0 == rpmsg_lite_is_link_up(s_rpmsg)){ }
Freertos wait: while(xEventGroupWaitBits(rpmsgGroup, RPMSG_WAIT_FOR_LINK, FALSE, TRUE, portMAX_DELAY) & (RPMSG_WAIT_FOR_LINK) == 0){}

so if rpmsg_lite_tx_callback do this: rpmsg_lite_dev->link_state = 1U; in case of freertos it can do also
xEventGroupSetBits(rpmsgGroup,RPMSG_WAIT_FOR_LINK)

erpc/erpc_c/transports/erpc_rpmsg_lite_rtos_transport.cpp

Line 170 in 99675ec

while (0 == rpmsg_lite_is_link_up(s_rpmsg))