ASoC: sn95031: remove dead makefile about sn95031

All sn95031 stuff was removed in commit 987da3fe ("ASoC: sn95031: remove this code")
Since SND_SOC_SN95031 was gone, remove makefile about it.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/Makefile

@@ -387,7 +387,6 @@ obj-$(CONFIG_SND_SOC_SIGMADSP)	+= snd-soc-sigmadsp.o
 obj-$(CONFIG_SND_SOC_SIGMADSP_I2C)	+= snd-soc-sigmadsp-i2c.o
 obj-$(CONFIG_SND_SOC_SIGMADSP_REGMAP)	+= snd-soc-sigmadsp-regmap.o
 obj-$(CONFIG_SND_SOC_SI476X)	+= snd-soc-si476x.o
-obj-$(CONFIG_SND_SOC_SN95031)	+=snd-soc-sn95031.o
 obj-$(CONFIG_SND_SOC_SPDIF)	+= snd-soc-spdif-rx.o snd-soc-spdif-tx.o
 obj-$(CONFIG_SND_SOC_SIRF_AUDIO_CODEC) += sirf-audio-codec.o
 obj-$(CONFIG_SND_SOC_SSM2518)	+= snd-soc-ssm2518.o