SPM: Change type of thread p_context_ctrl

In practice, this is always a struct context_ctrl *, and using that type
allows us to remove several typecasts and gain compiler type-checking.

Same type change flows through to some tfm_arch_* functions. In two of
those, they can also be const.

Change-Id: If46ff5c75af132f55d4f5e292d78730edd75baf4
Signed-off-by: Chris Brand <chris.brand@cypress.com>
5 files changed