i2c: amd756: Fix endianness handling for word data

i2c: amd756: Fix endianness handling for word data

Ensure correct handling of "endianness"
for word-sized data in amd756_access

 - Convert word data into little-endian using cpu_to_le16
 - Convert word data from little-endian
   to cpu native format using le16_to_cpu

This fixes poteential issues on big-endian systems and
ensure proper byte ordering for SMBus word transacitions

Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
Link: https://lore.kernel.org/r/20250101103422.30523-1-evepolonium@gmail.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>