boards: adi: Enable new nodes of MAX32650 boards

This commit enables dma, i2c, spi, wdt and rtc_counter nodes for
MAX32650EVKIT and MAX32650FTHR boards.

Initial parts of the SRAM is used during the boot process, this causes
problems for some tests (e.g. tests/drivers/watchdog/wdt_basic_api).
To avoid these problems, this commit changes choosen SRAM to SRAM4.

Signed-off-by: Furkan Akkiz <hasanfurkan.akkiz@analog.com>
Signed-off-by: Burak Babaoglu <burak.babaoglu@analog.com>