ASoC: Davinci: Fix FS polarity for I2S format

Commit 75d9ac4 ("ASoC: Allow DAI formats to be specified in the dai_link")
changed DAI format flag values and we cannot simply invert anymore e.g.
frame-sync with ^= SND_SOC_DAIFMT_NB_IF (which was anyway misuse) as there
is no anymore fixed bit position for bit-clock or frame-sync inversion.

Fix this by relying only on DAI format flag values passed to us and by not
making any assumption on individual bit positions

Signed-off-by: Jarkko Nikula <jarkko.nikula@bitmer.com>
Cc: Vaibhav Bedia <vaibhav.bedia@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/davinci/davinci-i2s.c

@@ -265,6 +265,7 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 	struct davinci_mcbsp_dev *dev = snd_soc_dai_get_drvdata(cpu_dai);
 	unsigned int pcr;
 	unsigned int srgr;
+	bool inv_fs = false;
 	/* Attention srgr is updated by hw_params! */
 	srgr = DAVINCI_MCBSP_SRGR_FSGM |
 		DAVINCI_MCBSP_SRGR_FPER(DEFAULT_BITPERSAMPLE * 2 - 1) |
@@ -330,7 +331,7 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 		 * more empty bit clock slots between channels as the sample
 		 * rate is lowered.
 		 */
-		fmt ^= SND_SOC_DAIFMT_NB_IF;
+		inv_fs = true;
 	case SND_SOC_DAIFMT_DSP_A:
 		dev->mode = MOD_DSP_A;
 		break;
@@ -394,6 +395,8 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 	default:
 		return -EINVAL;
 	}
+	if (inv_fs == true)
+		pcr ^= (DAVINCI_MCBSP_PCR_FSXP | DAVINCI_MCBSP_PCR_FSRP);
 	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SRGR_REG, srgr);
 	dev->pcr = pcr;
 	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_PCR_REG, pcr);