These are identical to ````pios_usart<#>_dsm_cfg```` for all uarts.  Rather than repeating the identical data for HSUM, just rename the existing DSM versions of these config structs as ````pios_usart<#>_dsm_hsum_cfg```` and make sure that the config structs are defined when *either* ````PIOS_INCLUDE_DSM```` or ````PIOS_INCLUDE_HSUM```` is defined.