snd_soc_msm: Correct the default decimator volume

- wcd9310 register dump says that 68 is correct, not 67

Change-Id: I6f1734a1d46b857f9182fc14bc5d67dc68d906c7
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_device_motorola_moto_msm8960 into kitkat