utils: avoid dividing by zero when multiplying y/z by 0/x
utils: avoid dividing by zero when multiplying y/z by 0/x

The gcd of 0/x is 0, and this is then used as a denominator.

cfoch/gstreamer,cfoch/gstreamer,mparis/gstreamer,cablelabs/gstreamer,centricular/gstreamer,jpxiong/gstreamer,surround-io/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,Lachann/gstreamer,StreamUtils/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,shelsonjava/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,mparis/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,centricular/gstreamer,krichter722/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,surround-io/gstreamer,centricular/gstreamer,cablelabs/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,surround-io/gstreamer,krichter722/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,cfoch/gstreamer,cablelabs/gstreamer,surround-io/gstreamer,krichter722/gstreamer,mparis/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer