I2C: OMAP2+: Name registers in I2C IP V2 only accordingly

The OMAP I2C driver dynamically chooses between two register sets of
differing sizes depending on the cpu type it finds itself on.

It has been observed that the existing code references non-existing
registers on OMAP3530, because while it correctly chose the smaller
register layout based on cpu type, the code uses the probed register
ID to decide if to execute code referencing an extra register, and
both register layout devices on OMAP3530 and OMAP4430 report the same
probed ID of 0x40.

This patch changes the extended register names only found on IP V2
of the I2C peripheral unit accordingly to help show up errors in usage.

Cc: patches@linaro.org
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andy Green <andy.green@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Kevin Hilman <khilman@ti.com>