Remove bcopy(), bzero(), bcmp()

bcopy() has a confusing argument order and is actually a move, not a
copy; they're all deprecated since POSIX.1-2001 and removed in -2008,
and we shim them out to mem*() on Linux anyway

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12996

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

@@ -771,7 +771,6 @@ spl_init(void)
 {
 	int rc = 0;
 
-	bzero(&p0, sizeof (proc_t));
 	spl_random_init();
 
 	if ((rc = spl_kvmem_init()))