gdma_stop() function

- ESP_OK: Stop DMA engine successfully - ESP_ERR_INVALID_ARG: Stop DMA engine failed because of invalid argument - ESP_ERR_INVALID_STATE: Stop DMA engine failed because of invalid state, e.g. the channel is controlled by ETM, so can't stop it manually - ESP_FAIL: Stop DMA engine failed because of other error

This function is allowed to run within ISR context This function is also allowed to run when Cache is disabled, if `CONFIG_GDMA_CTRL_FUNC_IN_IRAM` is enabled