drm_hwcomposer: Use __ANDROID_API__ instead of PLATFORM_SDK_VERSION

__ANDROID_API__ definition is available by default in AOSP and NDK.

It also exported by standard system clang when the user sets
the '-target <ARCH>-linux-android<LEVEL>' compiler flag.

Reason for this change is integration of meson build script, where
otherwise the user has to provide the API level manually.

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
diff --git a/hwc2_device/DrmHwcTwo.h b/hwc2_device/DrmHwcTwo.h
index 29f61da..7a65853 100644
--- a/hwc2_device/DrmHwcTwo.h
+++ b/hwc2_device/DrmHwcTwo.h
@@ -30,7 +30,7 @@
 
   std::pair<HWC2_PFN_HOTPLUG, hwc2_callback_data_t> hotplug_callback_{};
   std::pair<HWC2_PFN_VSYNC, hwc2_callback_data_t> vsync_callback_{};
-#if PLATFORM_SDK_VERSION > 29
+#if __ANDROID_API__ > 29
   std::pair<HWC2_PFN_VSYNC_2_4, hwc2_callback_data_t> vsync_2_4_callback_{};
   std::pair<HWC2_PFN_VSYNC_PERIOD_TIMING_CHANGED, hwc2_callback_data_t>
       period_timing_changed_callback_{};