fix(Examples,PeriphDrivers): Fix clock option value setting for UART-…

[kilicomercan]

…IBRO and UART-ERTCO clocks in MAX78000.

Description

-> UART3 is has low power capability and it works with IBRO and ERTCO clocks. We must set UART3_CTRL->bclksrc register bits to a value between 0-3. IBRO and ERTCO is defined as 2 and 3 in the MAX78000 user guide. However, the correct values seem to be 0 and 1 to set UART baudrate clock source to IBRO and ERTCO clocks respectively.

-> I updated the function definitions for the part to make the UART example work successfully. I tested the code for both clock options with MAX78000 FTHR.

UART3 is initialized with IBRO clock by default in the example.

[sihyung-maxim]

Thanks Omercan.

These UART clock source settings in uart_me17.c and uart_ai85.c have been updated countless times because of the incorrect user guide. (I guess that also means some reviewers and developers don't test or verify changes... lol).

Anyways, I've submitted a Jira ticket a while ago, and these changes have been addressed internally and will be visible when the updated UGs are published.