I2C: OMAP2+: use platform_data ip revision to select register map

Change the register map names to reflect the IP revision they
are representing, and use the platform_data IP revision index
to select between them at init time.

Eliminates 1 of 17 cpu_...() calls in the driver.

Cc: patches@linaro.org
Cc: Ben Dooks <ben-linux@fluff.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>