i2c: xiic: Add standard mode support for > 255 byte

read transfers

Added standard mode for AXI I2C controller to enable read transfers
of size more than 255 bytes. The driver selects standard mode in the
following scenarios.

1. If a single message request comes from user space, requesting a
read of more than 255 bytes

2. If a message set request comes from user space consisting of many
messages and if any one of them is a read operation, irrespective
of the size of transfer. (This is done because it is observed that
repeated start operation is not happening in dynamic mode read as
expected in a message set request from user space.)

Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>