m32r: consistently use "suffix-$(...)"

Commit a556bec9 ("m32r: fix arch/m32r/boot/compressed/Makefile")
changed "$(suffix_y)" to "$(suffix-y)", but didn't update any location
where "suffix_y" is set, causing:

  make[5]: *** No rule to make target `arch/m32r/boot/compressed/vmlinux.bin.', needed by `arch/m32r/boot/compressed/piggy.o'.  Stop.
  make[4]: *** [arch/m32r/boot/compressed/vmlinux] Error 2
  make[3]: *** [zImage] Error 2

Correct the other locations to fix this.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/m32r/boot/compressed/Makefile

@@ -43,9 +43,9 @@ endif
 
 OBJCOPYFLAGS += -R .empty_zero_page
 
-suffix_$(CONFIG_KERNEL_GZIP)	= gz
-suffix_$(CONFIG_KERNEL_BZIP2)	= bz2
-suffix_$(CONFIG_KERNEL_LZMA)	= lzma
+suffix-$(CONFIG_KERNEL_GZIP)	= gz
+suffix-$(CONFIG_KERNEL_BZIP2)	= bz2
+suffix-$(CONFIG_KERNEL_LZMA)	= lzma
 
 $(obj)/piggy.o: $(obj)/vmlinux.scr $(obj)/vmlinux.bin.$(suffix-y) FORCE
 	$(call if_changed,ld)