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/bsd-user/main.c b/bsd-user/main.c
index ae24723..76ab359 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -861,7 +861,7 @@
     }
 
     /* init debug */
-    cpu_set_log_filename(log_file);
+    qemu_set_log_filename(log_file);
     if (log_mask) {
         int mask;
         const CPULogItem *item;