i2c: rtl9300: introduce F_BUSY to the reg_fields struct

i2c: rtl9300: introduce F_BUSY to the reg_fields struct

In RTL9607C i2c controller the busy check operation is done on the
separate bit of the command register as opposed to self clearing
command trigger bit on the rtl9300 and rtl9310 i2c controllers.

Introduce a new F_BUSY field to the reg_fields struct for that
and change the regmap read poll function to use F_BUSY
instead of I2C_TRIG.

Signed-off-by: Rustam Adilov <adilov@disroot.org>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260401180648.337834-4-adilov@disroot.org