plat/arm/board/fvp: Add support for Measured Boot ...

This patch adds support for Measured Boot functionality
to FVP platform code. It also defines new properties
in 'tpm_event_log' node to store Event Log address and
it size
'tpm_event_log_sm_addr'
'tpm_event_log_addr'
'tpm_event_log_size'
in 'event_log.dtsi' included in 'fvp_tsp_fw_config.dts'
and 'fvp_nt_fw_config.dts'. The node and its properties
are described in binding document
'docs\components\measured_boot\event_log.rst'.

Change-Id: I087e1423afcb269d6cfe79c1af9c348931991292
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>