gdma_append() function

- ESP_OK: Send append command to DMA engine successfully - ESP_ERR_INVALID_ARG: Send append command to DMA engine failed because of invalid argument - ESP_FAIL: Send append command to 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 This API could also resume a paused DMA engine, make sure new descriptors have been appended to the descriptor chain before calling it.