mx53loco: Remove unused get_board_rev function
No board information is passed for MX53LOCO, so remove get_board_rev function.
Cc: Jason Liu <r64343@freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Jason Liu <r64343@freescale.com>