MBHC initialisation can fail so add the missing error handling to avoid
dereferencing an error pointer when later configuring the jack:

    Unable to handle kernel paging request at virtual address fffffffffffffff8

    pc : wcd_mbhc_start+0x28/0x380 [snd_soc_wcd_mbhc]
    lr : wcd938x_codec_set_jack+0x28/0x48 [snd_soc_wcd938x]

    Call trace:
     wcd_mbhc_start+0x28/0x380 [snd_soc_wcd_mbhc]
     wcd938x_codec_set_jack+0x28/0x48 [snd_soc_wcd938x]
     snd_soc_component_set_jack+0x28/0x8c [snd_soc_core]
     qcom_snd_wcd_jack_setup+0x7c/0x19c [snd_soc_qcom_common]
     sc8280xp_snd_init+0x20/0x2c [snd_soc_sc8280xp]
     snd_soc_link_init+0x28/0x90 [snd_soc_core]
     snd_soc_bind_card+0x628/0xbfc [snd_soc_core]
     snd_soc_register_card+0xec/0x104 [snd_soc_core]
     devm_snd_soc_register_card+0x4c/0xa4 [snd_soc_core]
     sc8280xp_platform_probe+0xf0/0x108 [snd_soc_sc8280xp]

Fixes: bcee7ed0 ("ASoC: codecs: wcd938x: add Multi Button Headset Control support")
Cc: stable@vger.kernel.org      # 5.15
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230703124701.11734-1-johan+linaro@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>