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.cpp b/hwc2_device/DrmHwcTwo.cpp
index 4accb07..6facac3 100644
--- a/hwc2_device/DrmHwcTwo.cpp
+++ b/hwc2_device/DrmHwcTwo.cpp
@@ -196,7 +196,7 @@
       vsync_callback_ = std::make_pair(HWC2_PFN_VSYNC(function), data);
       break;
     }
-#if PLATFORM_SDK_VERSION > 29
+#if __ANDROID_API__ > 29
     case HWC2::Callback::Vsync_2_4: {
       vsync_2_4_callback_ = std::make_pair(HWC2_PFN_VSYNC_2_4(function), data);
       break;
@@ -239,7 +239,7 @@
     hwc2_display_t displayid, int64_t timestamp,
     [[maybe_unused]] uint32_t vsync_period) const {
   /* vsync callback */
-#if PLATFORM_SDK_VERSION > 29
+#if __ANDROID_API__ > 29
   if (vsync_2_4_callback_.first != nullptr &&
       vsync_2_4_callback_.second != nullptr) {
     vsync_2_4_callback_.first(vsync_2_4_callback_.second, displayid, timestamp,
@@ -255,7 +255,7 @@
 void DrmHwcTwo::SendVsyncPeriodTimingChangedEventToClient(
     [[maybe_unused]] hwc2_display_t displayid,
     [[maybe_unused]] int64_t timestamp) const {
-#if PLATFORM_SDK_VERSION > 29
+#if __ANDROID_API__ > 29
   hwc_vsync_period_change_timeline_t timeline = {
       .newVsyncAppliedTimeNanos = timestamp,
       .refreshRequired = false,