PSCI: Fix MISRA defects in platform code

Fix violations of MISRA C-2012 Rules 10.1, 10.3, 13.3, 14.4, 17.7 and
17.8.

Change-Id: I6c9725e428b5752f1d80684ec29cb6c52a5c0c2d
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
4 files changed