module/cdns_i2c: Enhance I2C error handling

Bump up the I2C interface timeout to the maximum value
supported by the IP. This is particularly useful when
communicating with slow I2C target devices.

Also, reset the I2C FIFO at the start of a Tx/Rx
sequence in order to clear any error state latched for
a previously failed transaction.

Change-Id: I3c7aa91fcc5515c41c482cdc0249b6b0024ad616
Signed-off-by: Anurag Koul <anurag.koul@arm.com>