Instead of adding missing definitions to the existing at91sam9_ddrsdr.h
and adapting the incoming DDRAM initialization code from at91bootstrap,
just replace the lightly used existing header with:
https://github.com/linux4sam/at91bootstrap/blob/v3.8.12/include/arch/at91_ddrsdrc.h

For easier comprehension, the replacement is done in three steps:
Here the header is imported.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>