espressif: Use Philips data format for i2s

it's the standard i2s format, and what's needed for max98357 breakout.

Author: jepler

ports/espressif/common-hal/audiobusio/I2SOut.c

@@ -53,7 +53,7 @@ void common_hal_audiobusio_i2sout_construct(audiobusio_i2sout_obj_t *self,
 
     i2s_std_config_t i2s_config = {
         .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(48000),
-        .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO),
+        .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO),
         .gpio_cfg = {
             .mclk = main_clock != NULL ? main_clock->number : I2S_GPIO_UNUSED,
             .bclk = bit_clock->number,