Add a Peripheral Support section to the board page listing the GPIO and
MCU_MCSPI0 drivers, and replace the "UART console only" warning on both
the chip and board pages -- it no longer describes the port. The
replacement states what actually constrains the port: NuttX runs on the
R5F under RemoteProc and depends on the bootloader or Linux Device
Manager having powered and clocked the peripherals, because there is no
TISCI client yet.
Assisted-by: Claude Code:claude-opus-5
Signed-off-by: Ulaş Sertan Kemeç <sertan.usk@gmail.com>