[PATCH] ARM: OMAP: Add RNG platform device

The following patch adds a platform device for the OMAP RNG. I have
added support for using this to the RNG driver as part of a generic
RNG codebase I'm writing and will submit that for testing once
it is compiling.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>