feat(mpmm): add support for MPMM

MPMM - the Maximum Power Mitigation Mechanism - is an optional
microarchitectural feature present on some Armv9-A cores, introduced
with the Cortex-X2, Cortex-A710 and Cortex-A510 cores.

MPMM allows the SoC firmware to detect and limit high activity events
to assist in SoC processor power domain dynamic power budgeting and
limit the triggering of whole-rail (i.e. clock chopping) responses to
overcurrent conditions.

This feature is enabled via the `ENABLE_MPMM` build option.
Configuration can be done via FCONF by enabling `ENABLE_MPMM_FCONF`, or
by via the plaform-implemented `plat_mpmm_topology` function.

Change-Id: I77da82808ad4744ece8263f0bf215c5a091c3167
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/lib/fconf/fconf.mk b/lib/fconf/fconf.mk
index 18bcb35..fb88910 100644
--- a/lib/fconf/fconf.mk
+++ b/lib/fconf/fconf.mk
@@ -14,3 +14,6 @@
 
 FCONF_AMU_SOURCES	:=	lib/fconf/fconf_amu_getter.c
 FCONF_AMU_SOURCES	+=	${FDT_WRAPPERS_SOURCES}
+
+FCONF_MPMM_SOURCES	:=	lib/fconf/fconf_mpmm_getter.c
+FCONF_MPMM_SOURCES	+=	${FDT_WRAPPERS_SOURCES}