Measured Boot Driver: Fix MISRA-C 2012 defects ...

This patch fixes MISRA C-2012 Pointers and Arrays
Rule 18.4 defects reported by Coverity scan:
"misra_c_2012_rule_18_4_violation: Using arithmetic on pointer "

Change-Id: I06753b28467c473e346b9871c1657284fc43a3f3
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>

TF-A: Add Event Log for Measured Boot ...

This patch adds support for Event Log generation required
for Measured Boot functionality.

Change-Id: I34f05a33565e6659e78499d62cc6fb00b7d6c2dc
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>