Open access to the UART and timer from non-privileged mode

[tdrozdovsky]

Describe the bug
It is necessary to open access to the UART and timer memory from non-privileged mode. (see setting PMP)

Remove

ifdef BL808
void MPU_bflb_uart_putchar(struct bflb_device_s *uart0, int character)
{
        BaseType_t xRunningPrivileged;

        xPortRaisePrivilege( xRunningPrivileged );
        bflb_uart_putchar(uart0, character);
        vPortResetPrivilege( xRunningPrivileged );
}
#endif

from mpu_wrappers.c