Merge changes from topic "srm/Errata_ABI_El3" into integration

* changes:
  docs(errata_abi): document the errata abi changes
  feat(fvp): enable errata management interface
  fix(cpus): workaround platforms non-arm interconnect
  refactor(errata_abi): factor in non-arm interconnect
  feat(errata_abi): errata management firmware interface

diff --cc Makefile
Simple merge

diff --cc bl31/bl31.mk
Simple merge

diff --cc docs/getting_started/build-options.rst
Simple merge

diff --cc make_helpers/defaults.mk
Simple merge

diff --cc plat/arm/board/fvp/platform.mk
index f2df780c65f8c7962914c33e35560fb47849acf8,363d15d2c0c9deccb2bc07cfb30f05f1f3b3dde6..863eb0e656b84dd2e9a19672c51dea24178c376a
--- 1/plat/arm/board/fvp/platform.mk
--- 2/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@@ -518,9 -513,10 +518,13 @@@ ifeq (${PLATFORM_TEST_EA_FFH}, 1
  BL31_SOURCES  += plat/arm/board/fvp/aarch64/fvp_ea.c
  endif
  
 -ifeq (${SPD},spmd)
 -BL31_SOURCES  +=      plat/arm/board/fvp/fvp_spmd.c
 +$(eval $(call add_define,PLATFORM_TEST_RAS_FFH))
 +ifeq (${PLATFORM_TEST_RAS_FFH}, 1)
 +    ifeq (${RAS_EXTENSION}, 0)
 +         $(error "PLATFORM_TEST_RAS_FFH expects RAS_EXTENSION to be 1")
 +    endif
  endif
+ 
+ ifeq (${ERRATA_ABI_SUPPORT}, 1)
+ include plat/arm/board/fvp/fvp_cpu_errata.mk
+ endif