i2c-bfin-twi: Add platform_resource interface to support multi-port TWI controllers

 - Dynamic alloc the resource of TWI driver data according to board information
 - TWI register read/write accessor based on dynamic regs_base
 - Support TWI0/TWI1 for BF54x

Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>