Add include files for prototypes

Include the header with prototypes in the file that provides definitions
as well, to catch any mismatch between prototype and definition.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470

module/zfs/lz4.c

@@ -33,6 +33,7 @@
  */
 
 #include <sys/zfs_context.h>
+#include <sys/zio_compress.h>
 
 static int real_LZ4_compress(const char *source, char *dest, int isize,
     int osize);