Core: Move spm header files to 'spm' folder

- Move 'spm_xxx.h' to 'spm' folder, they should belong to 'spm'.
- Fix and simplify inclusion of header file.
- Fix format and typo error.

Change-Id: I129c6626ddffbbdba0e7edc27e9307f0d6ea9b79
Signed-off-by: Mingyang Sun <mingyang.sun@arm.com>
39 files changed