b06228ec7e
* bug fixed gpio_mode_set miss gd32_spi->mosi_pin,gd32_spi->sck_pin * feature,add gd32_spi's alt_func_num member for different spi periph's gpio * feature,add spi3,spi4,and support multi spi devices * feature,add rt_hw_spi_device_attach api * tested on the gd32f450i-eval board