Merge branch '2022-04-11-initial-valgrind-support'

Merge branch '2022-04-11-initial-valgrind-support'

To quote the author:
This series adds support for running valgrind against U-Boot's internal
malloc. This allows for much more useful reports to be generated.

Some example output of valgrind run against u-boot/master with this
branch applied may be found at [1]. Note that valgrind gives up around
acpi.  This feature still needs a lot of work on suppressions/hints to
filter out the noise properly.

[1] https://gist.githubusercontent.com/Forty-Bot/199bf06f9cdd6871e54f8f484c16e111/raw/2a2f99108eef84b48e27a54332f3f71f4e2e5342/gistfile1.txt