Or without subqueries:

SELECT TOP 1 @@servername AS Servername

,[min server memory (MB)] = MAX(CASE WHEN name = 'min server memory (MB)' THEN value END )

,[max server memory (MB)] = MAX(CASE WHEN name = 'max server memory (MB)' THEN value END )

FROM sys.configurations

WHERE name IN('min server memory (MB)', 'max server memory (MB)')