Android: generate an error if building on Android 4.4 or earlier

Since commit 7a5b5f52260 ("Android: drop Android 4.4 (KitKat) support"),
Android 4.4 or earlier is no longer supported, so exit with an error if we
try building on it.

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/Android.mk b/Android.mk
index ab6bf6a..de37f46 100644
--- a/Android.mk
+++ b/Android.mk
@@ -32,6 +32,9 @@
 MESA_TOP := $(call my-dir)
 
 MESA_ANDROID_MAJOR_VERSION := $(word 1, $(subst ., , $(PLATFORM_VERSION)))
+ifneq ($(filter 2 4, $(MESA_ANDROID_MAJOR_VERSION)),)
+$(error "Android 4.4 and earlier not supported")
+endif
 
 MESA_DRI_MODULE_REL_PATH := dri
 MESA_DRI_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/$(MESA_DRI_MODULE_REL_PATH)