test: provide unit test for memory functions

Memory functions may have architecture specific implementations. These
should be tested.

Provide unit tests for memset(), memcpy(), memmove().

Provide a 'ut lib' sub-command to execute the tests.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
7 files changed