av1_dx_iface: fix ambiguous var name.
av1_dx_iface: fix ambiguous var name.

Change-Id: I92e75411b12c7c05023e2cde3d7db80aacf4e2fd

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom