[U-Boot] [PATCH v2] AT91: add RTT and GPBR based RTC

[Reinhard Meyer]

Dear Xu, Hong,
> Some of Atmel's ARM926EJS chips have builtin RTC, for example, SAM9G45 SAM9M10 SAM9RL and new X5 serials.
> May we take this into account at this stage?
Maybe you can help me here:
the 9260 and the 9XE-ENG Sample (soldered on my EK)
have the GPBRs at 0xfffffd50.
Its sold as a feature (but I think its a bug) that the
current Mask of the 9XE has the GPBRs at 0xfffffd60 (0xfffffd50
designated "reserved" now).
Is there a simple way to distinguish between both masks?

Reinhard