MAINTAINERS: assign sandbox drivers to SANDBOX

Drivers should have a maintainer.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 41c9f26..91d40ea 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1336,6 +1336,7 @@
 S:	Maintained
 F:	arch/sandbox/
 F:	doc/arch/sandbox.rst
+F:	drivers/*/*sandbox*.c
 F:	include/dt-bindings/*/sandbox*.h
 
 SEAMA