lib/decompress_inflate.c: include appropriate header file

Include appropriate header file include/linux/decompress/inflate.h in
lib/decompress_inflate.c because it has prototype declaration of
function defined in lib/decompress_inflate.c.

Also, fix the guard around the header file
include/linux/decompress/inflate.h to use a more unique guard symbol.
This avoids conflict with the INFLATE_H defined by
zlib_inflate/inflate.h.

This eliminates the following warning in lib/decompress_inflate.c:

  lib/decompress_inflate.c:35:17: warning: no previous prototype for `gunzip' [-Wmissing-prototypes]
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/decompress/inflate.h

-#ifndef INFLATE_H
-#define INFLATE_H
+#ifndef LINUX_DECOMPRESS_INFLATE_H
+#define LINUX_DECOMPRESS_INFLATE_H
 
 int gunzip(unsigned char *inbuf, int len,
 	   int(*fill)(void*, unsigned int),

lib/decompress_inflate.c

@@ -19,6 +19,7 @@
 #include "zlib_inflate/inflate.h"
 
 #include "zlib_inflate/infutil.h"
+#include <linux/decompress/inflate.h>
 
 #endif /* STATIC */