configure.ac: fix build error.
configure.ac: fix build error.

updating GST_PLUGIN_LDFLAGS in configure.ac to fix build error in
version 1.14.4

Signed-off-by: Sandeep Sheriker M <edd1a9544e0de4a557bbc2a542a98a5d73afd835@microchip.com>

linux4sam/gst1-hantro-g1,linux4sam/gst1-hantro-g1