i2c: omap24xx_i2c: Use platdata to probe the device

This allows the driver to be used without OF_CONTROL.
AM335x support DM_SPL but does not use SPL_OF_CONTROL. Enabling DM_I2C in
SPL thus requires that the omap I2C can be passed platdata.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>