board: am65x: Use generic AM6x board detection function

board: am65x: Use generic AM6x board detection function

Replace the board-specific implementation of do_board_detect()
with a call to the generic do_board_detect_am6() function to
avoid code duplication across AM6x family boards.

The generic function provides the same functionality with
additional fallback logic to try alternate EEPROM addresses.

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Signed-off-by: Guillaume La Roque (TI.com) <glaroque@baylibre.com>