includes: move tb_flush into its own header

This aids subsystems (like gdbstub) that want to trigger a flush
without pulling target specific headers.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

Message-Id: <20230302190846.2593720-8-alex.bennee@linaro.org>
Message-Id: <20230303025805.625589-8-richard.henderson@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 5340de0..118efa5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -136,6 +136,7 @@
 F: docs/devel/tcg*
 F: include/exec/cpu*.h
 F: include/exec/exec-all.h
+F: include/exec/tb-flush.h
 F: include/exec/helper*.h
 F: include/sysemu/cpus.h
 F: include/sysemu/tcg.h