fs: clean up after mandatory file locking support removal

Commit 3efee0567b4a ("fs: remove mandatory file locking support") removes
some operations in functions rw_verify_area().

As these functions are now simplified, do some syntactic clean-up as
follow-up to the removal as well, which was pointed out by compiler
warnings and static analysis.

No functional change.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>

fs/read_write.c

@@ -365,12 +365,8 @@ out_putf:
 
 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
 {
-	struct inode *inode;
-	int retval = -EINVAL;
-
-	inode = file_inode(file);
 	if (unlikely((ssize_t) count < 0))
-		return retval;
+		return -EINVAL;
 
 	/*
 	 * ranged mandatory locking does not apply to streams - it makes sense
@@ -381,12 +377,12 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
 
 		if (unlikely(pos < 0)) {
 			if (!unsigned_offsets(file))
-				return retval;
+				return -EINVAL;
 			if (count >= -pos) /* both values are in 0..LLONG_MAX */
 				return -EOVERFLOW;
 		} else if (unlikely((loff_t) (pos + count) < 0)) {
 			if (!unsigned_offsets(file))
-				return retval;
+				return -EINVAL;
 		}
 	}