compat/linux: Add Linux i2c-dev ioctl compatibility support

Implement Linux I2C ioctl translation in the Linux compatibility layer
and wire iicbus cdevs up for in-kernel rdwr handling.
Support common i2c-dev requests including SLAVE, FUNCS, and RDWR,
while rejecting unsupported 10-bit and SMBus operations.

Signed-off-by: YAO, Xin <mr.yaoxin@outlook.com>
Reviewed by: imp, adrian, pouria
Differential Revision: https://reviews.freebsd.org/D56251