powerpc/mm: Return directly after a failed __copy_from_user() in sys_subpage_prot()

This function already has multiple exit points, so there's no harm
adding another. Although it looks odd to return directly in a function
which takes a lock, we've actually just dropped the mmap_sem in this
code, so there's really no reason to go via a label. And it means we can
drop the unhelpfully named out2 label.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[mpe: Rewrite change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/subpage-prot.c

@@ -248,9 +248,8 @@ long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map)
 			nw = (next - addr) >> PAGE_SHIFT;
 
 		up_write(&mm->mmap_sem);
-		err = -EFAULT;
 		if (__copy_from_user(spp, map, nw * sizeof(u32)))
-			goto out2;
+			return -EFAULT;
 		map += nw;
 		down_write(&mm->mmap_sem);
 
@@ -262,6 +261,5 @@ long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map)
 	err = 0;
  out:
 	up_write(&mm->mmap_sem);
- out2:
 	return err;
 }