MIPS: Quiet the building output of vmlinux.32 and vmlinux.64

Based on quiet_cmd_X and cmd_X, this patch quiets the building output of
vmlinux.32 and vmlinux.64.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Sam Ravnborg <sam@ravnborg.org>
Patchwork: https://patchwork.linux-mips.org/patch/1766/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

@@ -285,15 +285,19 @@ endif
 # Other need ECOFF, so we build a 32-bit ELF binary for them which we then
 # convert to ECOFF using elf2ecoff.
 #
+quiet_cmd_32 = OBJCOPY $@
+	cmd_32 = $(OBJCOPY) -O $(32bit-bfd) $(OBJCOPYFLAGS) $< $@
 vmlinux.32: vmlinux
-	$(OBJCOPY) -O $(32bit-bfd) $(OBJCOPYFLAGS) $< $@
+	$(call cmd,32)
 
 #
 # The 64-bit ELF tools are pretty broken so at this time we generate 64-bit
 # ELF files from 32-bit files by conversion.
 #
+quiet_cmd_64 = OBJCOPY $@
+	cmd_64 = $(OBJCOPY) -O $(64bit-bfd) $(OBJCOPYFLAGS) $< $@
 vmlinux.64: vmlinux
-	$(OBJCOPY) -O $(64bit-bfd) $(OBJCOPYFLAGS) $< $@
+	$(call cmd,64)
 
 all:	$(all-y)