zero: set default systemimage-size to smallest known one
zero: set default systemimage-size to smallest known one

Change-Id: I1b3b3ac99728ac1dc4860dda13dd743bd33facfa

TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common,TeamNexus/android_device_samsung_zero-common