[vulkan] Set min_buffer_count

Currently we set min_buffer_count_for_camping, which doesn't make sense
(since it's the application that decides how the buffers are used,
not the driver). min_buffer_count, which was recently added, makes more
sense.

Change-Id: I480ff5a6987cb14017c1b15012687f52d6ec9507
diff --git a/system/vulkan_enc/ResourceTracker.cpp b/system/vulkan_enc/ResourceTracker.cpp
index b9ceccc..2663c65 100644
--- a/system/vulkan_enc/ResourceTracker.cpp
+++ b/system/vulkan_enc/ResourceTracker.cpp
@@ -1336,7 +1336,7 @@
                                    fuchsia::sysmem::vulkanUsageTransferSrc |
                                    fuchsia::sysmem::vulkanUsageTransferDst |
                                    fuchsia::sysmem::vulkanUsageSampled;
-        constraints.min_buffer_count_for_camping = 1;
+        constraints.min_buffer_count = 1;
         constraints.has_buffer_memory_constraints = true;
         fuchsia::sysmem::BufferMemoryConstraints& buffer_constraints =
             constraints.buffer_memory_constraints;