CRIS v32: Replace build flags in boot/rescue/Makefile

- Change AFLAGS to asflags-y, LDFLAGS to ldflags-y and EXTRA_CFLAGS
  to ccflags-y. We only need the flags in this Makefile.

arch/cris/arch-v32/boot/rescue/Makefile

@@ -3,11 +3,11 @@
 #
 
 CC = gcc-cris -mlinux -march=v32 $(LINUXINCLUDE)
-EXTRA_CFLAGS = -O2
-AFLAGS += -I $(TOPDIR)/include/asm/arch/mach/ -I $(TOPDIR)/include/asm/arch
-EXTRA_CFLAGS += -I $(TOPDIR)/include/asm/arch/mach/ -I $(TOPDIR)/include/asm/arch
+ccflags-y += -O2 -I $(srctree)/include/asm/arch/mach/ \
+		-I $(srctree)/include/asm/arch
+asflags-y += -I $(srctree)/include/asm/arch/mach/ -I $(srctree)/include/asm/arch
 LD = gcc-cris -mlinux -march=v32 -nostdlib
-LDFLAGS = -T $(obj)/rescue.ld
+ldflags-y += -T $(obj)/rescue.ld
 LDPOSTFLAGS = -lgcc
 OBJCOPY = objcopy-cris
 OBJCOPYFLAGS = -O binary --remove-section=.bss