soc: arm: cypress: psoc6: Update soc.h includes

Update <soc.h> include files.  This removes the unnecessary
<kernel_includes.h> file.  In addition, add <sys/util.h> to
expose macros and <devicetree.h> following general standards.

Signed-off-by: Gerson Fernando Budke <gerson.budke@atl-electronics.com>