CC3200: Fix boot loader regression

Go back to Ubuntu 16.04 and older gcc-arm (4.9.3).

Boot loader just won't run when compiled with newer GCC (7.x).
It's likely that it can be fixed with compile switches but I couldn't figure it out quickly, so going to just downgrade for now to get it back to workign state.

CL: CC3200: Fix boot loader regression

PUBLISHED_FROM=b70b03bd17e03c7dae02328b32b855f3ca3ad6a9

src/common/platforms/cc3200/gcc.mk

@@ -29,11 +29,11 @@ $(SDK_OBJS): CFLAGS += -include common/platform.h
 
 # cc flags,file
 define cc
-	$(vecho) "GCC   $2 -> $@"
+	$(vecho) "GCC   $2"
 	$(Q) $(CC_WRAPPER) $(CC) -c $1 -o $@ $2
 endef
 define cxx
-	$(vecho) "G++   $2 -> $@"
+	$(vecho) "G++   $2"
 	$(Q) $(CC_WRAPPER) $(CXX) -c $1 -o $@ $2
 endef