drm_hwcomposer: Implement getDisplayConfigurations

This deprecates calls like getDisplayConfigs and getDisplayAttribute.
Once HWC2 support has been removed from drm_hwcomposer, the legacy calls
could be implemented by calling getDisplayConfigurations.

The main different between the two is that in HWC3, the dpi is in
dots-per-inch and its unit is float. In HWC2, the dpi is in
dots-per-1000-inches and its unit is int32.

Change-Id: I9eed17d6f575bc05f1794dc0575f268fe1fc297d
Signed-off-by: Drew Davenport <ddavenport@google.com>
diff --git a/hwc2_device/HwcDisplay.cpp b/hwc2_device/HwcDisplay.cpp
index 789ac79..36333d2 100644
--- a/hwc2_device/HwcDisplay.cpp
+++ b/hwc2_device/HwcDisplay.cpp
@@ -347,8 +347,8 @@
   return HWC2::Error::None;
 }
 
-HWC2::Error HwcDisplay::GetDisplayConfigs(uint32_t *num_configs,
-                                          hwc2_config_t *configs) {
+HWC2::Error HwcDisplay::LegacyGetDisplayConfigs(uint32_t *num_configs,
+                                                hwc2_config_t *configs) {
   uint32_t idx = 0;
   for (auto &hwc_config : configs_.hwc_configs) {
     if (hwc_config.second.disabled) {