i2c: lpc32xx: Force consistent bus numbering

i2c: lpc32xx: Force consistent bus numbering

Normally, this would probably be done by adding devicetree aliases
to the main dtsi file for the lpc32xx and using bus->req_seq instead.

Since we want to have consistent i2c numbering, we cannot force the
bus->req_seq because. If for instance we have 3 buses numbered
from 0 to 2 with i2c0 enabled, i2c1 disabled and i2c2 enabled;
i2c2 can be selected using 'i2c dev 1' and 'i2c dev 2' commands
because a bus can be probed using req_seq or seq interchangeably.

Signed-off-by: Liam Beguin <lbeguin@tycoint.com>
Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>