m32r: add memcpy() for CONFIG_KERNEL_GZIP=y

Fix the m32r link error:

    LD      arch/m32r/boot/compressed/vmlinux
  arch/m32r/boot/compressed/misc.o: In function `zlib_updatewindow':
  misc.c:(.text+0x190): undefined reference to `memcpy'
  misc.c:(.text+0x190): relocation truncated to fit: R_M32R_26_PLTREL against undefined symbol `memcpy'
  make[5]: *** [arch/m32r/boot/compressed/vmlinux] Error 1

by adding our own implementation of memcpy().

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/m32r/boot/compressed/misc.c

@@ -39,6 +39,16 @@ static void *memset(void *s, int c, size_t n)
 #endif
 
 #ifdef CONFIG_KERNEL_GZIP
+void *memcpy(void *dest, const void *src, size_t n)
+{
+	char *d = dest;
+	const char *s = src;
+	while (n--)
+		*d++ = *s++;
+
+	return dest;
+}
+
 #define BOOT_HEAP_SIZE             0x10000
 #include "../../../../lib/decompress_inflate.c"
 #endif