camera: pin cpp_std to gnu++17

This project doesn't build with gnu++20 and prevents AOSP default to be
upgraded to a newer standard. Once the build failure is fixed here, this
change can be reverted.

Bug: 311052584
Test: m checkbuild
Change-Id: I416bde51a2a1f1ad58d9c2b0acee037839b16d52
diff --git a/camera/ndk/Android.bp b/camera/ndk/Android.bp
index 24a11e3..0d20f52 100644
--- a/camera/ndk/Android.bp
+++ b/camera/ndk/Android.bp
@@ -111,6 +111,7 @@
 
 cc_library_shared {
     name: "libcamera2ndk_vendor",
+    cpp_std: "gnu++17",
     vendor: true,
     srcs: [
         "ndk_vendor/impl/ACameraDevice.cpp",