qemu-log: add log category for unimplemented functionality

Add new log category (LOG_UNIMP) for unimplemented functionality.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/qemu-log.c b/qemu-log.c
index 1dd3de4..1ec70e7 100644
--- a/qemu-log.c
+++ b/qemu-log.c
@@ -120,6 +120,8 @@
     { CPU_LOG_IOPORT, "ioport",
       "show all i/o ports accesses" },
 #endif
+    { LOG_UNIMP, "unimp",
+      "log unimplemented functionality" },
     { 0, NULL, NULL },
 };