core: remove unnecessary NULL checks for g_free()

g_free() already check if the given pointer is NULL and does nothing on
a NULL pointer.

libmm-glib/mm-location-gps-raw.c

@@ -217,8 +217,7 @@ mm_location_gps_raw_add_trace (MMLocationGpsRaw *self,
 
     if (g_regex_match (self->priv->gga_regex, trace, 0, &match_info)) {
         /* UTC time */
-        if (self->priv->utc_time)
-            g_free (self->priv->utc_time);
+        g_free (self->priv->utc_time);
         self->priv->utc_time = g_match_info_fetch (match_info, 1);
 
         /* Latitude */

src/mm-base-sms.c

@@ -215,10 +215,8 @@ generate_3gpp_submit_pdus (MMBaseSms *self,
     }
 
     /* Free array (not contents, which were taken for the part) */
-    if (split_text)
-        g_free (split_text);
-    if (split_data)
-        g_free (split_data);
+    g_free (split_text);
+    g_free (split_data);
 
     /* Set additional multipart specific properties */
     if (n_parts > 1) {

src/mm-broadband-bearer.c

@@ -1376,8 +1376,7 @@ detailed_disconnect_finish (MMBroadbandBearer *self,
 static void
 detailed_disconnect_context_free (DetailedDisconnectContext *ctx)
 {
-    if (ctx->cgact_command)
-        g_free (ctx->cgact_command);
+    g_free (ctx->cgact_command);
     g_object_unref (ctx->data);
     g_object_unref (ctx->primary);
     if (ctx->secondary)