This code goes in your child functions.php file.

// Removes et_add_viewport_meta from the wp_head phase
function remove_divi_actions() {
remove_action( 'wp_head', 'et_add_viewport_meta' );
}

// Call 'remove_divi_actions' during WP initialization
add_action('init','remove_divi_actions');

function et_add_viewport_meta_2() {
    echo '<meta name="viewport" content="width=device-width, initial-scale=1.0">';
}
add_action('wp_head', 'et_add_viewport_meta_2');
Code language: PHP (php)

Source: https://www.facebook.com/groups/diviwebdesigners/permalink/1881237912246570/