Add a method to override a master

EVS considers the client, which owns the display, as the high priority
client and allows it to steal a master role from existing master that
does not own the display.

Bug: 139536751
Test: VtsHalEvsV1_1Target
Change-Id: Idecaeedd90f187de57de912a09f4782bfb81a996
Signed-off-by: Changyeon Jo <changyeon@google.com>