hwmon: (tps23861) reduce count of i2c transactions for port_status

hwmon: (tps23861) reduce count of i2c transactions for port_status

When reading the 'port_status' debugfs entry, some I2C registers were
read more than once. This looks inefficient in an I2C trace.

To reduce I2C traffic, update tps23861_port_status_show() to only read
each register once. Indexing the port number from 0 instead of 1 also
allows simplifying things a bit.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Link: https://lore.kernel.org/r/20220907015405.16547-1-mr.nuke.me@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>