omap4-common: fix definition of mode (it's a string, not an array of strings)

Change-Id: Ib5b58e2e3b5ae317a0eedb82e08f1dc5f85ff877
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_device_motorola_omap4-common into cm-11.0