i2c: mxc: Make 'no gpio pinctrl state' print as debug

Some I2C bus devicetree nodes, doesn't require to have
gpio pinctrl so replace the dev_info to debug so the
print never comes on the console and for bus that uses
gpio pinctrl anyway have dev_err.

Before:
------
U-Boot> i2c dev 1
Setting bus to 1
i2c bus 1 at 0x21a4000, no gpio pinctrl state.

After:
------
U-Boot> i2c dev 1
Setting bus to 1

Cc: Simon Glass <sjg@chromium.org>
Cc: Heiko Schocher <hs@denx.de>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Heiko Schocher <hs@denx.de>