Set the correct clkdev-name for the i2c clock.

It also get's rid of the ARCH_NR_GPIOS define on the rationale
that isn't an ARCH-wide setting anyway. If a device has two
pca953x devices, the reserved number will be wrong.
Signed-off-by: NHolger Schurig <hs4233@mail.mn-solutions.de>

Signed-off-by: <hs4233@mail.mn-solutions.de>

Based on code from "Martin Fuzzey" <mfuzzey@gmail.com>
Signed-off-by: NHolger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>