ARM: at91: remove mach/at91_ramc.h and mach/at91rm9200_mc.h

mach/at91_ramc.h and mach/at91rm9200_mc.h aren't necessary anymore, remove them.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>