perf: fix reproducibility in 5.19+

perf: fix reproducibility in 5.19+

kernels with upstream commit 630af16eee495f583db5202c3613d1b191f10694
[perf tools: Use Python devtools for version autodetection rather than
runtime], or -stable backports of that commmit, evade our substitutions
for reproducibility.

We add a second sed expression to ensure that our definition of python
is used, as we have the proper environement setup and don't need the
full path of python, which eventually will be captured by the perf
binaries.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>