Remove upload file types filter for admin

This is example for only doc file for admin.

You are also add another file to avoid restriction for admin.

add_filter( 'wp_check_filetype_and_ext', 'file_and_ext_allow_for_user', 10, 4 );
function file_and_ext_allow_for_user( $types, $file, $filename, $mimes )
{
    if( is_admin() ){
        if( false !== strpos( $filename, '.doc' ) )
        {
            $types['ext'] = 'doc';
            $types['type'] = 'application/msword';
        }
    }

    return $types;
}