ctrl_set_svc_params: ensure framerate_factor[] is non-zero

Like `scaling_factor_num` and `scaling_factor_den`, make
`framerate_factor[]` a minimum of 1 to avoid a divide by zero.

Fixes:
av1/encoder/svc_layercontext.c:141:38: runtime error: division by zero

Bug: aomedia:416284454
Fixed: aomedia:416284454
Change-Id: Iee91b50e1a16f11f1d67398da1ecb2998288b246

av1/av1_cx_iface.c

diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index b1a6432..0740dcc 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -3962,7 +3962,7 @@
         } else {
           lc->layer_target_bitrate = 1000 * layer_target_bitrate;
         }
-        lc->framerate_factor = params->framerate_factor[tl];
+        lc->framerate_factor = AOMMAX(1, params->framerate_factor[tl]);
         if (tl == ppi->number_temporal_layers - 1)
           target_bandwidth += lc->layer_target_bitrate;
       }