v4l2dec: resolve invalid property id [1/1]

PD#SWPL-145305

Problem:
invalid property id 17 for "low-latency-mode" of
type 'GParamBoolean' in 'amlv4l2av1dec'

Solution:
add get property method

Verify:
ah212

Change-Id: Ie3740177125e43baa4208a564e669c6673c93ef3
Signed-off-by: hanghang.luo <hanghang.luo@amlogic.com>
diff --git a/src/gstamlv4l2object.c b/src/gstamlv4l2object.c
index 5b0add3..10cda33 100644
--- a/src/gstamlv4l2object.c
+++ b/src/gstamlv4l2object.c
@@ -823,6 +823,9 @@
     case PROP_ENABLE_NR:
         g_value_set_boolean(value, v4l2object->enable_nr);
         break;
+    case PROP_LOW_LATENCY_MODE:
+        g_value_set_boolean(value, v4l2object->low_latency_mode);
+        break;
     default:
         return FALSE;
         break;