drivers/xen/xenbus: Simplify return statement in join()

Don't unnecessarily negate 'buffer' and simplify the return statement.

Reviewed-by: Jason Andryuk <[e-mail]>
Signed-off-by: Thorsten Blum <[e-mail]>
Signed-off-by: Juergen Gross <[e-mail]>
Message-ID: <[e-mail]>

drivers/xen/xenbus/xenbus_xs.c

···
 		buffer = kasprintf(GFP_NOIO | __GFP_HIGH, "%s", dir);
 	else
 		buffer = kasprintf(GFP_NOIO | __GFP_HIGH, "%s/%s", dir, name);
-	return (!buffer) ? ERR_PTR(-ENOMEM) : buffer;
+	return buffer ?: ERR_PTR(-ENOMEM);
 }
 
 static char **split(char *strings, unsigned int len, unsigned int *num)