ASoC: wm8996: Fix enum ctl accesses in a wrong type

"DSP1 EQ Mode" and "DSP2 EQ Mode" ctls in wm8996 codec driver are
enum, while the current driver accesses wrongly via
value.integer.value[].  They have to be via value.enumerated.item[]
instead.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>