gst-imx: Fix md5sum after commit change, and correct build options

There were two issues with 0.9.7-2:
- The source commit had changed from 0.9.7-1, but the md5sum was not updated to reflect this.
- The package was not built with --egl-platform=fb, thus defaulting to relying on X (which was erroneous due to already depending on gpu-viv-bin-mx6q-fb). This caused the imxeglvivsink GStreamer element to not function.

This PR addresses both issues.