gunzip.c: Only include gzwrite on CONFIG_CMD_UNZIP

Only when we have CONFIG_CMD_UNZIP enabled do we have the 'gzwrite'
command.  While this command should be separated from CONFIG_CMD_UNZIP
we should also only include the write portion of the gz code in that
case as well.

Signed-off-by: Tom Rini <trini@konsulko.com>

lib/gunzip.c

@@ -70,6 +70,7 @@ int gunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp)
 	return zunzip(dst, dstlen, src, lenp, 1, i);
 }
 
+#ifdef CONFIG_CMD_UNZIP
 __weak
 void gzwrite_progress_init(u64 expectedsize)
 {
@@ -258,6 +259,7 @@ out:
 
 	return r;
 }
+#endif
 
 /*
  * Uncompress blocks compressed with zlib without headers