Fixed PAL cmake files for non-Windows builds

Gems/Atom/RPI/Code/Source/Platform/Android/PAL_android.cmake

@@ -0,0 +1,13 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set (PAL_TRAIT_BUILD_ATOM_RPI_ASSETS_SUPPORTED FALSE)
+set (PAL_TRAIT_BUILD_ATOM_RPI_MASKED_OCCLUSION_CULLING_SUPPORTED FALSE)

Gems/Atom/RPI/Code/Source/Platform/Linux/PAL_linux.cmake

@@ -10,3 +10,4 @@
 #
 
 set (PAL_TRAIT_BUILD_ATOM_RPI_ASSETS_SUPPORTED FALSE)
+set (PAL_TRAIT_BUILD_ATOM_RPI_MASKED_OCCLUSION_CULLING_SUPPORTED FALSE)

Gems/Atom/RPI/Code/Source/Platform/Mac/PAL_mac.cmake

@@ -10,3 +10,4 @@
 #
 
 set (PAL_TRAIT_BUILD_ATOM_RPI_ASSETS_SUPPORTED TRUE)
+set (PAL_TRAIT_BUILD_ATOM_RPI_MASKED_OCCLUSION_CULLING_SUPPORTED FALSE)

Gems/Atom/RPI/Code/Source/Platform/iOS/PAL_ios.cmake

@@ -0,0 +1,13 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set (PAL_TRAIT_BUILD_ATOM_RPI_ASSETS_SUPPORTED FALSE)
+set (PAL_TRAIT_BUILD_ATOM_RPI_MASKED_OCCLUSION_CULLING_SUPPORTED FALSE)