Remove gst-shark from excelsior-core

gst-shark will not be preinstalled in rootfs. This will save 280MB in
rootfs.img. The user can still install the package with apt-get.

Change-Id: I63164104e4e00a7ba16a5444c3458879773f6a0a
diff --git a/debian/control b/debian/control
index 1dc9c8d..806b7b9 100644
--- a/debian/control
+++ b/debian/control
@@ -16,7 +16,6 @@
          excelsior-tools,
          excelsior-vpu-prebuilts,
          excelsior-wlan,
-         gst-shark,
          iw,
          libgstreamer-gl1.0-0 (>= 1.14.4-2+mtk),
          linux-image-4.19.125-mtk,