vulkan-samples: Fix reproducibility issue

There is code to remove the prefix CMAKE_SOURCE_DIR from __FILENAME__ paths
used for logging with LOGE() in the code. We need to make this match the value we use
in the debug source remapping from CFLAGS. If we don't, the code is firstly removing
the incorrect prefix and possibly moving outside the string, secondly, it causes a
reproducibility issue depending on the length of path the build happens in.

Add a small patch and configuration to avoid the issue.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>