MIPS: Reduce kernel image size for !CONFIG_DEBUG_ZBOOT

!CONFIG_DEBUG_ZBOOT doesn't need puts() and puthex(), remove them and
the corrospindig strings for !CONFIG_DEBUG_ZBOOT, as a result, it saves
about 1280 bytes.

[ralf@linux-mips.org: Resolved reject.]

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/1898/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
index 31903cf..5483106 100644
--- a/arch/mips/boot/compressed/decompress.c
+++ b/arch/mips/boot/compressed/decompress.c
@@ -28,8 +28,13 @@
 extern unsigned char __image_begin, __image_end;
 
 /* debug interfaces  */
+#ifdef CONFIG_DEBUG_ZBOOT
 extern void puts(const char *s);
 extern void puthex(unsigned long long val);
+#else
+#define puts(s) do {} while (0)
+#define puthex(val) do {} while (0)
+#endif
 
 void error(char *x)
 {