Retire spl_module_init()/spl_module_fini()

In the original implementation of the SPL wrappers were provided
for module initialization and cleanup.  This was done to abstract
away any compatibility code which might be needed for the SPL.

As it turned out the only significant compatibility issue was that
the default pwd during module load differed under Illumos and Linux.
Since this is such as minor thing and the wrappers complicate the
code they are being retired.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#2985

module/splat/splat-ctl.c

@@ -50,7 +50,6 @@
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
-#include <linux/module_compat.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
@@ -600,7 +599,7 @@ static struct miscdevice splat_misc = {
 	.fops		= &splat_fops,
 };
 
-static int
+static int __init
 splat_init(void)
 {
 	int error;
@@ -636,7 +635,7 @@ splat_init(void)
 	return (error);
 }
 
-static int
+static void __exit
 splat_fini(void)
 {
 	int error;
@@ -665,12 +664,10 @@ splat_fini(void)
 	ASSERT(list_empty(&splat_module_list));
 	printk(KERN_INFO "SPLAT: Unloaded module v%s-%s%s\n",
 	    SPL_META_VERSION, SPL_META_RELEASE, SPL_DEBUG_STR);
-
-	return (0);
 }
 
-spl_module_init(splat_init);
-spl_module_exit(splat_fini);
+module_init(splat_init);
+module_exit(splat_fini);
 
 MODULE_DESCRIPTION("Solaris Porting LAyer Tests");
 MODULE_AUTHOR(SPL_META_AUTHOR);