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/os/linux/spl/spl-generic.c

@@ -39,6 +39,7 @@
 #include <sys/proc.h>
 #include <sys/kstat.h>
 #include <sys/file.h>
+#include <sys/sunddi.h>
 #include <linux/ctype.h>
 #include <sys/disp.h>
 #include <sys/random.h>