sparc: vDSO: fix return value of __setup handler

__setup() handlers should return 1 to obsolete_checksetup() in
init/main.c to indicate that the boot option has been handled.
A return of 0 causes the boot option/value to be listed as an Unknown
kernel parameter and added to init's (limited) argument or environment
strings. Also, error return codes don't mean anything to
obsolete_checksetup() -- only non-zero (usually 1) or zero.
So return 1 from vdso_setup().

Fixes: 9a08862a ("vDSO for sparc")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <izh1979@gmail.com>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Nick Alcock <nick.alcock@oracle.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Link: https://lore.kernel.org/r/20240211052808.22635-1-rdunlap@infradead.org

arch/sparc/vdso/vma.c

@@ -449,9 +449,8 @@ static __init int vdso_setup(char *s)
 	unsigned long val;
 
 	err = kstrtoul(s, 10, &val);
-	if (err)
-		return err;
-	vdso_enabled = val;
-	return 0;
+	if (!err)
+		vdso_enabled = val;
+	return 1;
 }
 __setup("vdso=", vdso_setup);