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/hwc2_device.cpp b/hwc2_device/hwc2_device.cpp
index 2242391..87a7705 100644
--- a/hwc2_device/hwc2_device.cpp
+++ b/hwc2_device/hwc2_device.cpp
@@ -244,7 +244,7 @@
       return ToHook<HWC2_PFN_VALIDATE_DISPLAY>(
           DisplayHook<decltype(&HwcDisplay::ValidateDisplay),
                       &HwcDisplay::ValidateDisplay, uint32_t *, uint32_t *>);
-#if PLATFORM_SDK_VERSION > 27
+#if __ANDROID_API__ > 27
     case HWC2::FunctionDescriptor::GetRenderIntents:
       return ToHook<HWC2_PFN_GET_RENDER_INTENTS>(
           DisplayHook<decltype(&HwcDisplay::GetRenderIntents),
@@ -255,7 +255,7 @@
           DisplayHook<decltype(&HwcDisplay::SetColorModeWithIntent),
                       &HwcDisplay::SetColorModeWithIntent, int32_t, int32_t>);
 #endif
-#if PLATFORM_SDK_VERSION > 28
+#if __ANDROID_API__ > 28
     case HWC2::FunctionDescriptor::GetDisplayIdentificationData:
       return ToHook<HWC2_PFN_GET_DISPLAY_IDENTIFICATION_DATA>(
           DisplayHook<decltype(&HwcDisplay::GetDisplayIdentificationData),
@@ -274,8 +274,8 @@
       return ToHook<HWC2_PFN_SET_DISPLAY_BRIGHTNESS>(
           DisplayHook<decltype(&HwcDisplay::SetDisplayBrightness),
                       &HwcDisplay::SetDisplayBrightness, float>);
-#endif /* PLATFORM_SDK_VERSION > 28 */
-#if PLATFORM_SDK_VERSION > 29
+#endif /* __ANDROID_API__ > 28 */
+#if __ANDROID_API__ > 29
     case HWC2::FunctionDescriptor::GetDisplayConnectionType:
       return ToHook<HWC2_PFN_GET_DISPLAY_CONNECTION_TYPE>(
           DisplayHook<decltype(&HwcDisplay::GetDisplayConnectionType),