qemu-log: Unify {cpu_set,set_cpu}_log_filename as qemu_set_log_filename

The qemu_log() functionality is no longer specific to TCG CPU debug logs.
Rename cpu_set_log_filename() to qemu_set_log_filename() and drop the
pointless wrapper set_cpu_log_filename().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/vl.c b/vl.c
index 1355f69..f9f4dda 100644
--- a/vl.c
+++ b/vl.c
@@ -3865,7 +3865,7 @@
      */
     if (log_mask) {
         if (log_file) {
-            set_cpu_log_filename(log_file);
+            qemu_set_log_filename(log_file);
         }
         set_cpu_log(log_mask);
     }