ASoC: wm8994: Add depends on MFD core

ASoC: wm8994: Add depends on MFD core

[ Upstream commit 5ed01155cea69801f1f0c908954a56a5a3474bed ]

The ASoC driver should not be used without the MFD component. This was
causing randconfig issues with regmap IRQ which is selected by the MFD
part of the wm8994 driver.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501061337.R0DlBUoD-lkp@intel.com/
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20250106154639.3999553-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>