Update to latest PowerVR to keep cmake source clean

The latest version of PowerVR_Examples includes a fix that I authored to
generate files in the binary directory so that the source directory
remains clean: https://github.com/powervr-graphics/Native_SDK/pull/52
(They manually applied my changes, so it was not merged directly).

Bug: b/161699652
Change-Id: Ic5747a17284489d7af523ce0c149916376eb2054
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/46688
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>
diff --git a/third_party/PowerVR_Examples b/third_party/PowerVR_Examples
index 0a5b48f..afdfce8 160000
--- a/third_party/PowerVR_Examples
+++ b/third_party/PowerVR_Examples
@@ -1 +1 @@
-Subproject commit 0a5b48fd1f4ad251f5b4f0e07c46744c4841255b
+Subproject commit afdfce88475e76c8f00686b89f4b2700c53ca283