cramfs: hide function prototypes behind __KERNEL__ macro

Currently, 3 kernel function prototypes are present in a header
file exported to userland. This patch fixes it.

Signed-off-by: Alexander Shishkin <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/cramfs_fs.h

···
 				| CRAMFS_FLAG_WRONG_SIGNATURE \
 				| CRAMFS_FLAG_SHIFTED_ROOT_OFFSET )
 
+#ifdef __KERNEL__
 /* Uncompression interfaces to the underlying zlib */
 int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen);
 int cramfs_uncompress_init(void);
 void cramfs_uncompress_exit(void);
+#endif /* __KERNEL__ */
 
 #endif