zephyr/src: Remove k_yield() at the end of console_irq_input_hook().

Some boards like the nrf52840dk crash immediatelly after boot when
k_yield() is executed in this function.  It also makes the REPL randomly
lock up on other boards like the nucleo_wb55rg.

Signed-off-by: danicampora <danicampora@gmail.com>

ports/zephyr/src/zephyr_getchar.c

@@ -46,7 +46,6 @@ static int console_irq_input_hook(uint8_t ch) {
  }
  // printk("%x\n", ch);
  k_sem_give(&uart_sem);
- k_yield();
  return 1;
 }