[urgent] RFR: JDK-8220155 JDK-8219971 broke hotspot build

[Magnus Ihse Bursie]

JDK-8219971 broke hotspot build since a needed TARGETS += was not 
included, instead the list of targets were reset by TARGETS :=.

Bug: https://bugs.openjdk.java.net/browse/JDK-8220155
Patch inline:
diff --git a/make/hotspot/gensrc/GensrcAdlc.gmk 
b/make/hotspot/gensrc/GensrcAdlc.gmk
--- a/make/hotspot/gensrc/GensrcAdlc.gmk
+++ b/make/hotspot/gensrc/GensrcAdlc.gmk
@@ -204,6 +204,6 @@
              {print}' \
             < $(ADLC_SUPPORT_DIR)/$* > $@

-  TARGETS := $(ADLC_GENERATED_FILES)
+  TARGETS += $(ADLC_GENERATED_FILES)

  endif

/Magnus