Hi,

 While fiddling with other serial port devices with the use of my HiFive
Unmatched board I have noticed we do not correctly report the baud base 
value for the SiFive FU740-C000 SOC's on-chip UARTs.  This small patch 
set fixes the initialisation of the baud base value and then simplifies 
handling by removing now redundant duplicate port parameter.

 See individual change descriptions for details.  This patch set has been 
verified with the HiFive Unmatched board.  Please apply.

  Maciej