Change "cfg count" to "cfg_count" in comment

"cfg_count" is the name of this struct member. The other comments use
the types of the struct members. Since the type of this struct member is
the generic 'int', this comment uses the struct member name instead.

Change-Id: I24f3a9cb375858f15ee8ca18abb649031e4527b4

av1/av1_cx_iface.c

diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index f0c4e1d..679a574 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -3800,7 +3800,7 @@
   },
   {
       // NOLINT
-      NELEMENTS(encoder_usage_cfg),  // cfg count
+      NELEMENTS(encoder_usage_cfg),  // cfg_count
       encoder_usage_cfg,             // aom_codec_enc_cfg_t
       encoder_encode,                // aom_codec_encode_fn_t
       encoder_get_cxdata,            // aom_codec_get_cx_data_fn_t