SPM: Add support for watermarking SPM stack

The IPC backend in a build without CONFIG_USE_TRUSTZONE set
allocates a dedicated SPM stack, rather than SPM using the
stack allocated to a partition.

Update the stack watermarking code (CONFIG_TFM_STACK_WATERMARKS)
so that this dedicated stack, if created, will also be watermarked
and the usage reported alongside the partition stack usage.

Change-Id: I51aeb98d85e4284a10b955bb0da7f96ee948e578
Signed-off-by: Chris Brand <chris.brand@cypress.com>
4 files changed