ASoC: mediatek: mt8195: silence uninitialized variable warning

ASoC: mediatek: mt8195: silence uninitialized variable warning

Smatch complains that we might hit the continue path on every iteration
through the loop.

    sound/soc/mediatek/mt8195/mt8195-mt6359-rt1019-rt5682.c:831
      mt8195_mt6359_rt1019_rt5682_card_late_probe()
    error: uninitialized symbol 'sof_comp'.

Initialize "sof_comp" to NULL to silence this warning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20211208151145.GA29257@kili
Signed-off-by: Mark Brown <broonie@kernel.org>