i2c: fsl-lpi2c: read lpi2c fifo size in probe()

The lpi2c fifo size is a read only parameter resides Parameter
Register. It's better to read lpi2c tx/rx fifo size in probe()
other than just define a macro for it.

Signed-off-by: Gao Pan <pandy.gao@nxp.com>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>