add SERCOM peripheral for UART debug

currently only the SERCOM peripheral driver is added an configured,
but it is not being used.
UART debug will be done through the EDBG COM port, on PB24/PB25 of
SAM E54 Xplained Pro board

Change-Id: Id7af37ce1dd2d0a356e019c96bf6438ce459411b
31 files changed
tree: 26b9de97c354cb6bb673c597041dcebdf29cdc57
  1. ccid/
  2. contrib/
  3. sysmoOCTSIM/