cc2538: spi: Do not call SPI_WAITFOREORx() at end of init
cc2538: spi: Do not call SPI_WAITFOREORx() at end of init

If the SSI has never been used and spi_init() is called, then the SSI receive
FIFO is empty and remains so, so calling SPI_WAITFOREORx() at the end of
spi_init() waits endlessly for SSI_SR.RNE to be set. Hence, this call must be
removed in order to avoid a deadlock.

Signed-off-by: Benoît Thébaudeau <835bc8b01b82c0117127b72626b289641d7633e2@advansee.com>

MohamedSeliem/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,bluerover/6lbr,arurke/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,bluerover/6lbr,MohamedSeliem/contiki,arurke/contiki,MohamedSeliem/contiki,arurke/contiki,arurke/contiki,arurke/contiki,arurke/contiki,arurke/contiki,bluerover/6lbr,MohamedSeliem/contiki