Updates openDisplay() API description

This change corrects the description of openDisplay()'s behavior when
new client requests to access a display resource.

Bug: 122671398
Test: N/A
Change-Id: Ic7380748f4907376563771498e8823ed739e09a6
Signed-off-by: Changyeon Jo <changyeon@google.com>
diff --git a/automotive/evs/1.0/IEvsEnumerator.hal b/automotive/evs/1.0/IEvsEnumerator.hal
index e1193d0..ee51e7e 100644
--- a/automotive/evs/1.0/IEvsEnumerator.hal
+++ b/automotive/evs/1.0/IEvsEnumerator.hal
@@ -57,7 +57,8 @@
      *
      * There can be at most one EVS display object for the system and this function
      * requests access to it. If the EVS display is not available or is already in use,
-     * a null pointer is returned.
+     * the old instance shall be closed and give the new caller exclusive
+     * access.
      * When done using the display, the caller may release it by calling closeDisplay().
      * TODO(b/36122635) Reliance on the sp<> going out of scope is not recommended because the
      * resources may not be released right away due to asynchronos behavior in the hardware binder.