refactor(amu): unify ENABLE_AMU and ENABLE_FEAT_AMUv1

So far we have the ENABLE_AMU build option to include AMU register
handling code for enabling and context switch. There is also an
ENABLE_FEAT_AMUv1 option, solely to protect the HAFGRTR_EL2 system
register handling. The latter needs some alignment with the new feature
scheme, but it conceptually overlaps with the ENABLE_AMU option.

Since there is no real need for two separate options, unify both into a
new ENABLE_FEAT_AMU name in a first step. This is mostly just renaming at
this point, a subsequent patch will make use of the new feature handling
scheme.

Change-Id: I97d8a55bdee2ed1e1509fa9f2b09fd0bdd82736e
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/Makefile b/Makefile
index ca97fc2..cc2ac6f 100644
--- a/Makefile
+++ b/Makefile
@@ -1092,7 +1092,6 @@
         DISABLE_MTPMU \
         DYN_DISABLE_AUTH \
         EL3_EXCEPTION_HANDLING \
-        ENABLE_AMU \
         ENABLE_AMU_AUXILIARY_COUNTERS \
         ENABLE_AMU_FCONF \
         AMU_RESTRICT_COUNTERS \
@@ -1172,7 +1171,7 @@
         ENABLE_TRBE_FOR_NS \
         ENABLE_BTI \
         ENABLE_PAUTH \
-        ENABLE_FEAT_AMUv1 \
+        ENABLE_FEAT_AMU \
         ENABLE_FEAT_AMUv1p1 \
         ENABLE_FEAT_CSV2_2 \
         ENABLE_FEAT_DIT \
@@ -1229,7 +1228,7 @@
         CTX_INCLUDE_NEVE_REGS \
         DECRYPTION_SUPPORT_${DECRYPTION_SUPPORT} \
         DISABLE_MTPMU \
-        ENABLE_AMU \
+        ENABLE_FEAT_AMU \
         ENABLE_AMU_AUXILIARY_COUNTERS \
         ENABLE_AMU_FCONF \
         AMU_RESTRICT_COUNTERS \
@@ -1310,7 +1309,6 @@
         ENABLE_MPMM \
         ENABLE_MPMM_FCONF \
         ENABLE_FEAT_FGT \
-        ENABLE_FEAT_AMUv1 \
         ENABLE_FEAT_ECV \
         SIMICS_BUILD \
         ENABLE_FEAT_AMUv1p1 \