build: use new toolchain variables for tools

This change migrates the values of `CC`, `CPP`, `AS` and other toolchain
variables to the new `$(toolchain)-$(tool)` variables, which were
introduced by the toolchain refactor patch. These variables should be
equivalent to the values that they're replacing.

Change-Id: I644fe4ce82ef1894bed129ddb4b6ab94fb04985d
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/tools/fiptool/Makefile b/tools/fiptool/Makefile
index 3cb89c6..865ff4c 100644
--- a/tools/fiptool/Makefile
+++ b/tools/fiptool/Makefile
@@ -61,8 +61,6 @@
   Q :=
 endif
 
-HOSTCC ?= gcc
-
 ifneq (${PLAT},)
 TF_PLATFORM_ROOT	:=	../../plat/
 include ${MAKE_HELPERS_DIRECTORY}plat_helpers.mk
@@ -84,14 +82,14 @@
 
 ${PROJECT}: ${OBJECTS} Makefile
 	@echo "  HOSTLD  $@"
-	${Q}${HOSTCC} ${OBJECTS} -o $@ $(LDOPTS)
+	${Q}$(host-cc) ${OBJECTS} -o $@ $(LDOPTS)
 	@${ECHO_BLANK_LINE}
 	@echo "Built $@ successfully"
 	@${ECHO_BLANK_LINE}
 
 %.o: %.c Makefile
 	@echo "  HOSTCC  $<"
-	${Q}${HOSTCC} -c ${CPPFLAGS} ${HOSTCCFLAGS} ${INCLUDE_PATHS} -MD -MP $< -o $@
+	${Q}$(host-cc) -c ${CPPFLAGS} ${HOSTCCFLAGS} ${INCLUDE_PATHS} -MD -MP $< -o $@
 
 -include $(DEPS)
 
diff --git a/tools/fiptool/plat_fiptool/st/stm32mp1/plat_fiptool.mk b/tools/fiptool/plat_fiptool/st/stm32mp1/plat_fiptool.mk
index 1ba47c1..0d69dbd 100644
--- a/tools/fiptool/plat_fiptool/st/stm32mp1/plat_fiptool.mk
+++ b/tools/fiptool/plat_fiptool/st/stm32mp1/plat_fiptool.mk
@@ -17,7 +17,7 @@
 HOSTCCFLAGS += -DPLAT_DEF_FIP_UUID
 
 ${PLAT_DEF_UUID_FILE_NAME}.o: plat_fiptool/st/stm32mp1/${PLAT_DEF_UUID_FILE_NAME}.c
-	${HOSTCC} -c ${CPPFLAGS} ${HOSTCCFLAGS} ${INCLUDE_PATHS} $< -o $@
+	$(host-cc) -c ${CPPFLAGS} ${HOSTCCFLAGS} ${INCLUDE_PATHS} $< -o $@
 
 PLAT_OBJECTS += ${PLAT_DEF_UUID_FILE_NAME}.o
 endif